This paper reviews the available literatures and research findings on the effect of caffeine on health and nutrition. Caffeine is a mild stimulant found in many of our favorite beverages and some of our foods, such as coffees, teas, colas, and even chocolate. Caffeine can negatively affect our health if it is not consumed in moderation. Caffeine can cause nutrient depletion of important nutrients, like vitamin B6, and interfere with nutrient absorption of essential minerals, including calcium, iron, magnesium and B vitamins. Studies have found caffeine consumption is associated with reduced risk of developing type 2 diabetes, although the mechanisms are unclear. However, sensitive sub-populations, including pregnant women, children and older individuals, and those with a history of heart disease, may experience effects at lower levels of caffeine and should limit their consumption to three cups of coffee per day, or no more than 300 mg/ day, to avoid adverse effects. Thus, the purpose of this paper is to review the effect of caffeine on health and nutrition. Introduction Caffeine is a naturally occurring chemical stimulant and an alkaloid belonging to a class of compounds called methylxanthines. Its chemical formula is C8-H10-N4-O2. Caffeine is one of the most comprehensively studied ingredients in the food supply. Yet, despite our considerable knowledge of caffeine and centuries of safe consumption in foods and beverages, questions and misperceptions about the potential health effects associated with caffeine persist (IFIC, 2003). Caffeine can act as antioxidant to prevent diseases. Antioxidants are substances that help protect cells in the body against damage acting as a defense against oxidative damage. The role of an antioxidant is to help reduce oxidation reactions and thus reduce damage to body tissues. Antioxidants have been linked to a number of potential health benefits, including protection against heart disease and most forms of cancer. Chlorogenic acid, caffeic acid, and melanoidins are all the types of antioxidants found in coffee. Coffee is one of a number of drinks that contain high antioxidant content. Antioxidants are also found in tea, cocoa and red wine. But there are four times more antioxidants in coffee than in tea (Escott-Stump, 2008). Caffeine rapidly absorbed following oral consumption peak blood (plasma) levels usually within 30 minutes. Then distributes into all body compartments – pass easily into brain, breast milk and crosses placenta. Then metabolized in the liver changed to di and mono-methylxanthines and finally filtered by the kidneys and they exit the body with the urine. How long it takes to leave caffeine from the body? it varies between individuals for example, an average adult – 3-5 hrs, child less than 6 months – 24 hrs, Pregnant – 7-8 hrs, and Smoker – 2-3 hrs (IFIC, 2003). At present, there is little evidence to show consumption of caffeine increases the risk of cancer. Studies have shown no negative association, and possibly some protective effects, between caffeine consumption and several types of cancer (IFIC, 2003). Caffeine consumption may help reduce the risk of several chronic diseases, including diabetes, liver disease, and cancer, as well as improve immune function but it has also risk for developing coronary artery disease, osteoporosis, gastritis, iron deficiency anemia, and still births (IFIC, 2003). Caffeine can cause nutrient depletion of important nutrients, like vitamin B6, and interfere with nutrient absorption of essential minerals, including calcium, iron, magnesium, and B vitamins (Escott-Stump, 2008).

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Effects of caffeine on health and nutrition: A Review

Tsedeke Wolde

Lecturer of Nutrition, Department of Public Health, College of Medical and Health Sciences, Wollega

University, Nekemte, Ethiopia

Abstract

This paper reviews the available literatures and research findings on the effect of caffeine on health and

nutrition. Caffeine is a mild stimulant found in many of our favorite beverages and some of our foods, such as

coffees, teas, colas, and even chocolate. Caffeine can negatively affect our health if it is not consumed in

moderation. Caffeine can cause nutrient depletion of important nutrients, like vitamin B6, and interfere with

nutrient absorption of essential minerals, including calcium, iron, magnesium and B vitamins. Studies have

found caffeine consumption is associated with reduced risk of developing type 2 diabetes, although the

mechanisms are unclear. However, sensitive sub-populations, including pregnant women, children and older

individuals, and those with a history of heart disease, may experience effects at lower levels of caffeine and

should limit their consumption to three cups of coffee per day, or no more than 300 mg/ day, to avoid adverse

effects. Thus, the purpose of this paper is to review the effect of caffeine on health and nutrition.

Key words: caffeine, health, diseases and nutrition.

Introduction

Caffeine is a naturally occurring chemical stimulant and an alkaloid belonging to a class of compounds called

methylxanthines. Its chemical formula is C8-H10-N4-O2. Caffeine is one of the most comprehensively studied

ingredients in the food supply. Yet, despite our considerable knowledge of caffeine and centuries of safe

consumption in foods and beverages, questions and misperceptions about the potential health effects associated

with caffeine persist (IFIC, 2003).

Caffeine can act as antioxidant to prevent diseases. Antioxidants are substances that help protect cells in the

body against damage acting as a defense against oxidative damage. The role of an antioxidant is to help reduce

oxidation reactions and thus reduce damage to body tissues. Antioxidants have been linked to a number of

potential health benefits, including protection against heart disease and most forms of cancer. Chlorogenic acid,

caffeic acid, and melanoidins are all the types of antioxidants found in coffee. Coffee is one of a number of

drinks that contain high antioxidant content. Antioxidants are also found in tea, cocoa and red wine. But there are

four times more antioxidants in coffee than in tea (Escott-Stump, 2008).

Caffeine rapidly absorbed following oral consumption peak blood (plasma) levels usually within 30 minutes.

Then distributes into all body compartments – pass easily into brain, breast milk and crosses placenta. Then

metabolized in the liver changed to di and mono- methylxanthines and finally filtered by the kidneys and they

exit the body with the urine. How long it takes to leave caffeine from the body? it varies between individuals for

example, an average adult – 3-5 hrs, child less than 6 months – 24 hrs, Pregnant – 7-8 hrs, and Smoker – 2-3 hrs

(IFIC, 2003).

At present, there is little evidence to show consumption of caffeine increases the risk of cancer. Studies have

shown no negative association, and possibly some protective effects, between caffeine consumption and several

types of cancer (IFIC, 2003).

Caffeine consumption may help reduce the risk of several chronic diseases, including diabetes, liver disease, and

cancer, as well as improve immune function but it has also risk for developing coronary artery disease,

osteoporosis, gastritis, iron deficiency anemia, and still births (IFIC, 2003). Caffeine can cause nutrient depletion

of important nutrients, like vitamin B6, and interfere with nutrient absorption of essential minerals, including

calcium, iron, magnesium, and B vitamins (Escott-Stump, 2008).

Most studies have found that caffeine consumption does not reduce bone mineral density in women who

consume adequate calcium. However, positive associations between caffeine consumption and hip fracture risk

in three studies imply that limiting coffee consumption to three cups per day (about 300 mg/day of caffeine) may

help prevent osteoporosis- related fractures in older adults (IFIC, 2003).

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Although epidemiological data on the effects of caffeine during pregnancy are conflicting, the evidence suggests

that women who are pregnant or are planning to become pregnant, or who are breastfeeding, can safely consume

caffeine, but should limit their consumption to three cups of coffee per day, providing no more than 300 mg/day

of caffeine (IFIC, 2003).

Sources of caffeine

Caffeine is a naturally occurring substance found in the leaves, seeds and/or fruits of at least 63 plant species

worldwide and is part of a group of compounds known as methylxanthines. The most commonly known sources

of caffeine are coffee, cocoa beans, kola nuts and tea leaves [Frary et al., 2005].

The amount of caffeine in food products varies depending upon the serving size, the type of product, and

preparation method. With teas and coffees, the plant variety also affects the caffeine content. An eight-ounce cup

of drip-brewed coffee typically has 65-120 mg caffeine; an eight-ounce serving of brewed tea has 20-90 mg; and

a 12- ounce canned soft drink has 30-60 mg [Knight, et al., 2004]. Energy drinks can contain 50- 160 mg or

more per eight-ounce serving, plus caffeine from guarana and other added sources not normally declared as

caffeine; and one ounce of solid milk chocolate typically has just six mg caffeine[ABA, 2007; Mayo Clinic,

2005].

Other sources of caffeine include over-the-counter pain relievers. Caffeine is an adjuvant—it increases the rate at

which the medication is absorbed into the body. It is also present in some stimulant tablets and cold medications.

Caffeine can be present in these products ranging from 16-200 mg [Cleveland Clinic, 2006].

Caffeine daily consumption intake

The per capita consumption level of caffeine for all consumers (of all ages) is approximately 120 mg per day, or

a mean intake of 1.73 mg/kg body weight/ day [Knight et al., 2004].

Children consume significantly less caffeine than adults. As of 2004, the average daily intake of caffeine by

young children ages 1-5 and 6-9 years from all caffeinated beverages was 14 and 22 mg/day, or 0.82 and 0.85

mg/kg body weight/day, respectively [Knight et al., 2004]. For children and young adults, the primary sources

of caffeine are soft drinks and teas, while for adults ages 25 and older; it is mostly derived from coffee [Knight et

al., 2004].

However, a growing beverage category, energy drinks, is a popular choice with several age groups, and is a

category to monitor for consumption in the coming years.

Evidence from both scientific reviews and specific studies on consumption of caffeine generally concludes that

daily consumption of 300 mg/day, or about three cups of coffee, is safe, even for more sensitive segments of the

population, such as young children and pregnant women [Nawrot et al., 2003].

Functions of caffeine

Caffeine is absorbed and passes quickly into the brain. It does not collect in the blood stream or get stored in the

body. It leaves the body in the urine many hours after it has been consumed. There is no nutritional need for

caffeine. It can be avoided in the diet. Caffeine stimulates, or excites, the brain and nervous system. It will not

reduce the effects of alcohol, although many people still believe a cup of coffee will help a person "sober-up."

Caffeine may be used for the short-term relief of fatigue or drowsiness (Escott-Stump, 2008).

Side effects of caffeine

Anxiety

Depression

Difficulty sleeping

Nausea

Restlessness

Tremors

A fast heart rate

Urinating more often

VomitingStopping caffeine abruptly may cause withdrawal symptoms, such as:-

Drowsiness

Headaches

Irritability

Nausea, and

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Vomiting

• Reduce caffeine gradually to prevent any symptoms of withdrawal.

• The effect of caffeine on health has been widely studied.

• Large amounts of caffeine may decrease bone mass density, most likely by interfering with the body's

ability to absorb calcium. This may lead to osteoporosis.

• Caffeine may cause or worsen painful, lumpy breasts (fibrocystic disease).

• Caffeine may have a negative effect on a child's nutrition if caffeinated drinks replace healthy drinks,

such as milk. A child who consumes caffeine may also eat less, because caffeine reduces the appetite (Escott-

Stump, 2008).

Effect of caffeine on health and diseases

Cardiovascular health

The relationship between coffee, caffeine and cardiovascular health markers has been explored, with emphasis

on cardiac arrhythmia, heart rate, serum cholesterol and blood pressure. In his review, Nawrot et al. (2003)

concluded that moderate caffeine consumption (400 mg or less, or four or fewer cups of coffee per day) does not

adversely affect cardiovascular health. Insufficient data exist to be able to draw conclusions about the risk of

coronary heart disease (CHD) or mortality associated with consumption of much higher amounts.

Hypertension (high blood pressure) is a recognized risk factor for CHD and stroke. Caffeine can acutely raise

heart rate and blood pressure immediately after consumption, although regular caffeine consumers can build up a

tolerance to these effects. Although the impact of coffee on blood pressure was first debated nearly thirty years

ago, extensive epidemiological studies have confirmed that there is no link between coffee consumption and

hypertension, hyperlipidemia, and coronary artery disease (CAD) (Nawrot et al., 2003). One study has linked

caffeine intake to abnormal heart rhythms, particularly premature atrial and ventricular contractions of the heart.

In this study, caffeine taken in tablet form resulted in blood pressure elevations four times greater than for

caffeinated coffee. Thus, although there appears to be no clear evidence for a strong causal relationship between

caffeinated coffee and abnormal heart rhythms, it is not as clear when considering caffeine alone or in beverages

other than coffee [Frishman and Sonnenblick, 2002].

Although scientific review author James (2004) suggested there is strong experimental evidence that blood

pressure remains reactive to caffeine in the diet, and that overall epidemiological evidence implicates caffeine as

a risk factor for hypertension, more recent studies on women have not supported this. According to the American

Heart Association (AHA)'s policy on caffeine, "Whether high caffeine intake increases the risk of coronary heart

disease is still under study" [AHA, 2007].

In the study by Lopez-Garcia et al. (2006), researchers found that coffee consumption was not associated with an

increased risk of CHD. In the Nurses' Health Studies I and II, coffee consumption, even at high levels, appeared

to have no effect on blood pressure; however, both regular and diet colas caused a modest increase in blood

pressure. This apparent contradiction was thought to be due either to an ingredient other than caffeine or by a

protective effect of another component of coffee. People already suffering from high blood pressure should

consult a physician about their caffeine intake, as they may be more sensitive to the effects of caffeine on blood

pressure [Winkelmeyer et al., 2005].

Reproductive health

There are several comprehensive review papers that examine the relationship between caffeine and reproductive

health. A review by Leviton and Cowan [2002] specifically examined outcomes such as delayed conception,

miscarriage (both chromosomally normal and aberrant), birth defects, premature birth, and low birth weight and

found that caffeine does not cause any of these outcomes. The authors concluded that the associations found in

the less rigorously analyzed studies could possibly be due to other factors, such as smoking.

Christian and Brent (2001) conducted a very systematic review on the relationship between caffeine

consumption by both pregnant women and women of child-bearing age and the occurrence of congenital

malformations, fetal growth retardation, small-for-date babies, miscarriages, behavioral effects, maternal

infertility and genetic effects.

The only statistically significant results were teratogenic (birth defect) effects in rats administered extremely

high levels of caffeine intravenously, which do not necessarily translate to humans and also could never be

attained merely by drinking beverages containing caffeine.

Fertility

Nawrot et al. (2003) noted in their review of caffeine that most epidemiological studies on caffeine and fertility

were affected by methodological issues, including inadequate measurement of caffeine intake, inadequate

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control for possible confounding factors, recall bias in retrospective studies, lack of data on frequency of

unprotected intercourse and, in some studies, inadequate sample size. Despite these limitations, the

epidemiological studies generally indicate that consumption of caffeine at levels at or below 300 mg per day, or

approximately three cups of coffee per day, did not reduce fertility in otherwise fertile women.

A study on the effects of alcohol and caffeine on fertility demonstrated a significant risk when alcohol and

caffeine were consumed together; however no effects were observed when caffeine was consumed alone

[Nawrot et al., 2003].

Miscarriage

There have been numerous epidemiological studies examining the relationship between coffee or caffeine intake

by pregnant women and the risk of miscarriage. Some studies have observed significant associations between

caffeine intakes greater than 300 mg/day, particularly from coffee, and the risk of miscarriage, whereas other

studies have not [Higdon and Frei, 2006]. While individual epidemiological studies cannot prove cause and

effect, they can contribute to the wealth of information on potential observed effects. However, they must be

taken within the context of the entire body of data [Nawrot et al., 2003].

Birth defects (teratology)

The majority of epidemiological studies have found that maternal caffeine consumption is not associated with

increased risk of congenital malformations, or birth defects, in fetuses [Higdon and Frei, 2006]. At present, there

is no convincing evidence from epidemiological studies that moderate caffeine consumption by pregnant women

ranging from 300–1,000 mg per day throughout the entire pregnancy increases the risk of birth defects [Nawrot

et al., 2003]. However, in light of other women's health issues, such as fertility and miscarriage, pregnant

women are advised to keep caffeine consumption at or below 300 mg/day (or approximately three cups of

coffee).

Bone health (osteoporosis)

Given the increased awareness of the incidence of osteoporosis in post-menopausal women, research on the

relationship between caffeine intake and bone health has been a particular area of focus. Consumption of large

amounts of caffeine (more than 744 mg/day) has been shown to increase urinary excretion of calcium and

magnesium [Tucker, 2003]. However, calcium excretion is complex and is affected by many other dietary

constituents such as calcium, potassium, phosphorus, isoflavones, antioxidants, salt, oxalate, phytates, and

protein [Massey, 2003; Atkinson and Ward, 2001]. Studies on caffeine and calcium metabolism and bone

deterioration show that, as caffeinated coffee consumption increases, milk consumption decreases. Bone

deterioration becomes more pronounced when dietary calcium is inadequate, and less pronounced when dietary

calcium intake is adequate.

Nawrot et al. (2003) concluded that caffeine's potential to adversely affect calcium balance and bone metabolism

is dependent on lifetime caffeine and calcium intakes, and is critical for women. Based on the data reviewed, the

authors suggested that caffeine intake of less than 400 mg/day does not have significant effects on bone density,

nor on calcium balance in individuals consuming at least 800 mg calcium per day. Higdon and Frei (2006) also

suggested that, although most studies have not found coffee or caffeine consumption to reduce bone mineral

density in women who consume adequate calcium, positive associations between caffeine consumption and hip

fracture risk in three prospective cohort studies suggest that limiting coffee consumption to three cups of coffee

per day (about 300 mg of caffeine per day) may help prevent hip-bone fractures in older adults.

Cancer

Most of the research on possible links between cancer and caffeine has been conducted on coffee and tea.

Therefore, it is extremely difficult to isolate the effects of caffeine unless the research specifically focuses on

caffeine. Consequently, research on caffeine and its effects on cancer, if any, is sparse. There are however,

references in coffee and tea research relating to caffeine that are generally positive.

Nawrot et al. (2003) concluded in his review of the research that caffeine is unlikely to be a human carcinogen at

levels below five cups of coffee per day (or less than 500 mg caffeine per day). Furthermore, the overall

evidence indicates that caffeine, as present in coffee, does not cause breast or bowel cancer. Moreover, although

early case control studies appeared to link caffeine intake to pancreatic, bladder and ovarian cancers, more

recent, better designed studies have not supported these conclusions [Tavani and La Vecchia, 2004; Zeegers et

al., 2004]. A number of case control studies have demonstrated reduced risk of colorectal cancer with coffee

consumption [Tavani and La Vecchia, 2004; Higdon and Frei, 2006]. In a review, Tavani and La Vecchia (2004)

showed that not only was there no risk of colon or colorectal cancer with caffeinated beverages, but there may

even be a protective effect. A study by Michels et al. (2005) confirmed that there is no association between rectal

cancer and consumption of caffeinated beverages.

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Reduced risk of diabetes

In both cohorts, higher caffeine intakes were associated with significant reductions in diabetes risk. In contrast,

tea consumption did not affect type 2 diabetes risks in either study [Salazar-Martinez, et al., 2004]. Van Dam and

Hu [2005] conducted a systematic review of nine cohort studies, including more than 193,000 men and women,

and found a 35% lower risk of type 2 diabetes in those who consumed at least six cups of coffee per day, and a

28% lower risk in those who consumed between four and six cups per day, compared to those who consumed

less than two cups per day. In another long-term study of the relationship between caffeinated beverage

consumption and incidence of type 2 diabetes, the authors followed more than 41,000 participants over ten years,

assessing coffee consumption every two to four years. The results suggest that caffeine intake from coffee and

other source is associated with a significantly lower risk for type 2 diabetes [Salazar-Martinez, et al., 2004].

Recovery from liver injury

The study conducted a prospective study to examine the relationship between coffee and tea consumption and

incidence of chronic liver disease [Ruhl and Everhart, 2005a]. The results showed that individuals who consume

more than two cups of coffee or tea per day have less than half the risk of developing chronic liver disease as

those who drink less than one cup of coffee per day.

Effect of caffeine on nutrition

The effect of caffeine on vitamin and minerals absorption

Caffeine is a mild stimulant found in many of our favorite beverages and some of our foods, such as coffees,

teas, colas, and even chocolate. Because caffeine can negatively affect our absorption of nutrients, it's important

to pay attention to the amount we consume. Moderate caffeine intake (300 mg or less per day) is probably not

harmful to most healthy adults; however, regular large amounts (over 350 mg per day) may cause dependency,

nutrient depletion, and interference with nutrient absorption. Many also take a multivitamin supplement daily as

a part of their morning routine. Not many people are aware that taking vitamins at the same time as a cup of

coffee or tea can interfere with the body's absorption of many necessary nutrients (Escott-Stump, 2008).

Calcium

Caffeine causes calcium to be excreted in the urine and feces. For every 150 mg of caffeine ingested, about the

amount in one cup of coffee, 5 mg of calcium is lost. This effect occurs even hours after the consumption of

caffeine. One study of postmenopausal women found that those who consumed more than 300 mg of caffeine

lost more bone in the spine than women who consumed less.

Caffeine also inhibits the amount of calcium that is absorbed through the intestinal tract and depletes the amount

retained by the bones. Studies have shown that women with high caffeine intake suffer more hip fractures than

those who avoid caffeine or drink in moderation (1 to 2 cups per day) (Escott-Stump, 2008).

Vitamin D

Caffeine inhibits vitamin D receptors, which limit the amount that will be absorbed. Because vitamin D is

important in the absorption and use of calcium in building bone, this could also decrease bone mineral density,

resulting in an increased risk for osteoporosis (Escott-Stump, 2008).

Iron

Caffeine interferes with the body's absorption of iron, which is necessary for red blood cell production. Drinking

caffeine at the same time as an iron source can reduce absorption by up to 80%, according to the Nutrition Desk

Reference. Any beverage containing caffeine should be separated from iron-containing foods or supplements by

at least one hour (Escott-Stump, 2008).

B Vitamins

Caffeine has a mild diuretic effect, which increases urination. Water soluble vitamins, such as the B-vitamins,

can be depleted as a result of the fluid loss. In addition, it interferes with the metabolism of some B-vitamins,

such as thiamine (vitamin B1). The one exception to this rule appears to be vitamin B12. Caffeine stimulates the

production of stomach acid, which actually helps the body absorb B12 (Escott-Stump, 2008).

Other Vitamins and Minerals

Caffeine may reduce the absorption of manganese, zinc and copper. It also increases the excretion of the

minerals magnesium, potassium, sodium and phosphate. There is also evidence that caffeine interferes with the

action of vitamin A (Escott-Stump, 2008).

Conclusion

As clearly discussed in the above review, there is evident that caffeine consumption at varying levels may help

reduce the risk of several chronic diseases. Sensitive sub-populations, including pregnant women, children and

older individuals, and those with a history of heart disease, may experience effects at lower levels of caffeine and

should limit their consumption to three cups of coffee per day, or no more than 300 mg/ day, to avoid adverse

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effects. Caffeine can cause nutrient deficiencies that can affect both health and quality of life. As with most

dietary factors, moderation and balance are keys in optimal nutrition intake.

Acknowledgment

The author would like to thanks Wollega University for the facilities available for literature search and technical

support.

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... Caffeine is an essential component of coffee that is also found in other common dietary sources such as tea, cocoa beans, chocolate, and medications [1,2]. The amount of caffeine in any food product depends on the serving size, the type of product, and how it is prepared [4]. Caffeine mobilizes intracellular calcium, inhibits phosphodiesterase, and binds to benzodiazepine receptors [5]. ...

... However, the effects of caffeine seem to be dosedependent [7,8]. For example, limiting caffeine consumption to three cups per day (equal to 300 mg/kg) can help prevent osteoporosis, whereas higher doses can increase the risk of osteoporosis [4]. The positive and negative effects of caffeine on health and several body functions have been investigated. ...

... The positive and negative effects of caffeine on health and several body functions have been investigated. Positive effects include decreased risk of cancer, liver disease, diabetes, cardiovascular disease [1,4], and Parkinson's disease [1], as well as reduced blood pressure [9]. Caffeine has also been found to improve cognitive performance (e.g. ...

Coffee, of which caffeine is a critical component, is probably the most frequently used psychoactive stimulant in the world. The effects of caffeine on the auditory and vestibular system have been investigated under normal and pathological conditions, such as acoustic trauma, ototoxicity, auditory neuropathy, and vestibular disorders, using various tests. Lower incidences of hearing loss and tinnitus have been reported in coffee consumers. The stimulatory effect of caffeine is represented by either a shorter latency or enhanced amplitude in electrophysiological tests of the auditory system. Furthermore, in the vestibular system, oculomotor testing revealed significant effects of caffeine, while other tests did not reveal any significant caffeine effects. It could be that caffeine improves transmission in the auditory and vestibular systems' central pathways. Importantly, the effects of caffeine seem to be dose-dependent. Also, inconsistent findings have been observed regarding caffeine's effects on the auditory and vestibular systems and related disorders. Overall, these findings suggest that caffeine does not strongly influence the peripheral auditory and vestibular systems. Instead, caffeine's effects seem to occur almost solely at the level of the central nervous system.

... The chemical formula of caffeine is C8-H10-N4-O2 and it is one of the most studied chemicals in food technology. Even with all the knowledge of caffeine and years of its consumption in beverages and food supply there is persistence of many question and gaps in understandings its health effects (IFIC, 2003) (Wolde WU-JU & Wolde, 2014) [81] . Though it contains high nutritive value, but more consumption of caffeine can be harmful for human health and it is slightly addictive. ...

... Across the globe energy drinks contains caffeine which affects both health and quality of life. Consumption of caffeine can lead to some diseases in sensitive population which includes, lactating and pregnant women, children, aged people (Wolde, 2014) [81] which leads to the need for an energy booster in energy drink which is not harmful to any age group and provides required nutrients. Herbal supplements are widely used all over the world, billions of dollars spends in recent years and many herbs have been studied but still there is gaps in knowledge. ...

... Across the globe energy drinks contains caffeine which affects both health and quality of life. Consumption of caffeine can lead to some diseases in sensitive population which includes, lactating and pregnant women, children, aged people (Wolde, 2014) [81] which leads to the need for an energy booster in energy drink which is not harmful to any age group and provides required nutrients. Herbal supplements are widely used all over the world, billions of dollars spends in recent years and many herbs have been studied but still there is gaps in knowledge. ...

... Caffeine and theobromine are naturally occurring methylxanthines with antioxidant potential [140] (Figure 3). There are some misconceptions regarding health effects caused by caffeine ingestion [140]. ...

... Caffeine and theobromine are naturally occurring methylxanthines with antioxidant potential [140] (Figure 3). There are some misconceptions regarding health effects caused by caffeine ingestion [140]. On the contrary, theobromine (and cocoa) consumption has demonstrated beneficial effects [141]. ...

... Similarly, caffeine consumption has been between 2.5-3 and 400 mg kg −1 bw (body weight) day −1 for children and adults, respectively [142,143]. The evidence is suggesting an alimentary impact as some nutrients are poorly absorbed when combined with alkaloids [140]. Caffeine analysis is common in the food industry (e.g., quality control in beverages) and research (e.g., alkaloid carrying plants); it has also been incorporated in academia and student curricula [144]. ...

... Its high prevalence of intake in the worldwide diet has arisen significant scientific interest in its effects on human health. Caffeine consumption has been studied as a risk factor for many diseases and conditions, including hypertension, cardiovascular diseases, bone density, various cancers, mental and behavioral disorders, and reproduction and developmental abnormalities [8][9][10] . However, studies to evaluate the effect of caffeine on hearing loss are contradictory. ...

  • Lili Long Lili Long
  • Yuedi Tang

Previous studies have reported the relationship between effect of caffeine and many diseases. However, studies to evaluate the association between caffeine and hearing loss are contradictory. To examine the relationship of urinary caffeine metabolites with the hearing threshold in US adults, a total of 849 adults aged 20–69 years who participated in the National Health and Nutrition Examination Survey (NHANES, 2011–2012) were enrolled in this study. Urinary caffeine and its 14 metabolites were applied as biomarkers to assess caffeine exposure. Hearing loss was defined as mean pure tone averages > 25 dB HL at 500, 1000, and 2000 Hz in both ears (low frequency); and 3000, 4000, and 6000 Hz in both ears (high frequency). Univariate and multivariate linear regression analyses were conducted to examine the associations of urinary caffeine metabolites with low- and high-frequency hearing thresholds, respectively. Low-frequency hearing loss were 5.08% and 6.10% in male and female participants, respectively; and high-frequency hearing loss were 31.81% and 15.14% in male and female participants, respectively. In the unadjusted model, the P value for trend shows that urinary caffeine metabolites 137X and AAMU were significantly associated with low-frequency PTA, and that 17X, 137X, AAMU were significantly associated with high-frequency PTA, but when the model was adjusted for sex, age, education level, firearm noise exposure, occupational noise exposure, recreational noise exposure, serum cotinine, body mass index, diabetes, hypertension, these were no longer statistically significant. In conclusion, urinary caffeine metabolites were not associated with the hearing threshold shifts in US adults.

... The purine alkaloid is present in coffee beans, tea leaves, cocoa beans, kola nuts (cola vera) and in nearly 60 species of other plants. Caffeine annual consumption is estimated at 120,000 tonnes [17,30]. In the daily food ration of a Central European resident, the content of this alkaloid ranges between 280-490 mg/day. ...

Background: Caffeine is the most widespread psychoactive substance in the world. With long-term consumption of caffeinated beverages, there is a high probability of overtaking on caffeine. Objective: The aim of the study was to estimate the consumption of caffeine in the daily caffeine intake of Polish consumers, determine the caffeinated products in the intake of this substance. Materials and methods: The survey was completed by 433 respondents living in Poland. The research tool was the electronic questionnaire, which consisted of: a) questions about personal data and measurement anthropometric and the level of physical activity and smoking; b) questions regarding the portion size and frequency of consumption of coffee, tea, cocoa, chocolate, energy drinks and colacarbonated beverages. Results: The main sources of caffeine in the respondents' diet include: coffee (Me 43.64 mg/d) and tea (Me 37.60 mg/d). Approximately 20% of respondents exceeded the threshold of daily caffeine intake (safety level for children and adolescents up to 3 mg/kg b.w, for adults up to 5.7 mg/kg b.w), considered safe. Conclusions: Respondents who have crossed the safe dose of caffeine intake, should limit the consumption of products being its main source (coffee).

... This present result supported the report of previous studies from Central Ethiopia [45], Kacha Bira district of Southern Ethiopia [53], Durame town Ethiopia [54], Debremarkos Hospital [21], and Kartum Sudan [55]. This might be because of the reason that coffee contains phenolic acid such as a chlorogenic acid that inhibits the absorption of nonhaem iron, which is necessary for red blood cell production [56,57]. ...

Background: Anemia is a situation in which the number and size of red blood cells, or the concentration of hemoglobin, fall below established cut-off values. Low hemoglobin level during pregnancy favors the alteration of placental angiogenesis and resulted in restricting the availability of nutrients to the fetus and consequently causing fetal growth retardation and low weight at birth. This study is aimed at assessing the hemoglobin level and associated factors among pregnant women in rural communities of Jimma zone, Southwest Ethiopia. Methods: A community-based cross-sectional study design was carried out among 367 pregnant women from June 1 to 30, 2020. Systematic random sampling was used to select study subjects. Hemoglobin level was measured by using HemoCue HB 301. An interviewer-administered structured questionnaire was used to collect the data. Descriptive statistics were used to describe the study subjects. A multivariable linear regression model was employed after the linearity, normality, multicollinearity, and homoscedasticity assumptions were checked. The unstandardized beta (β) coefficient along with a 95% confidence interval was computed to estimate the association between explanatory and dependant variables. Statistical significance was declared at P value < 0.05. Results: The mean (± SD) hemoglobin level of the respondents was 12.66 (±1.44) g/dl. The overall magnitude of anemia (hemoglobin level < 11 g/dl) among pregnant women was found to be 85 [23.16%, (95% CI: 18.3%-27.5%)]. Meal frequency [β = 0.40, (95% CI: 0.12, 0.69), P = 0.005], interpregnancy interval [β = 0.08, (95% CI: 0.02, 0.15), P = 0.007], mid-upper arm circumference measurement [β = 0.13, (95% CI: 0.07, 0.20), P ≤ 0.001], own fruits/vegetable [β = 0.55, (95% CI: 0.79, 0.31), P ≤ 0.001], coffee consumption [β = -1.00, (95% CI: -1.31, -0.68), P ≤ 0.001], and having history of still birth [β = -0.63, (95% CI: -1.06, -0.20), P = 0.004] were significantly associated with the hemoglobin level of pregnant women. Conclusions: Anemia was identified to be a moderate public health problem in the study area. Therefore, nutritional counseling should focus on the necessity of at least one extra meal, promotion of fruits/vegetable consumption, and improving the nutritional status of the women during antenatal care follow-up. Moreover, early screening and management of women with a history of stillbirth for anemia are also essential.

... In addition, the plasma levels needed to exert adverse developmental effects in humans are not attainable from ingesting large amounts of caffeine in foods and beverages. A profound review of 17 recent epidemiology (case-control and cohort) studies revealed no convincing evidence that moderate caffeine consumption by pregnant women ranging from 300 to 1000 mg per day throughout the entire pregnancy increases the risk of congenital malformations, miscarriage or birth defects (Brent et al., 2011;Wolde, 2014). According to EFSA (2015), prospective cohort studies show that caffeine intakes from all sources up to 200 mg per day consumed throughout the day by pregnant women in the general population do not give rise to safety concerns for the foetus. ...

This case study on the model substance caffeine demonstrates the viability of a 10-step read-across (RAX) framework in practice. New approach methodologies (NAM), including RAX and physiologically-based kinetic (PBK) modelling were used to assess the consumer safety of caffeine. Appropriate animal systemic toxicity data were used from the most relevant RAX analogue while assuming that no suitable animal toxicity data were available for caffeine. Based on structural similarities, three primary metabolites of the target chemical caffeine (theophylline, theobromine and paraxanthine) were selected as its most relevant analogues, to estimate a point of departure in order to support a next generation risk assessment (NGRA). On the basis of the pivotal mode of action (MOA) of caffeine and other methylxanthines, theophylline appeared to be the most potent and suitable analogue. A worst-case aggregate exposure assessment determined consumer exposure to caffeine from different sources, such as cosmetics and food/drinks. Using a PBK model to estimate human blood concentrations following exposure to caffeine, an acceptable Margin of Internal Exposure (MOIE) of 27-fold was derived on the basis of a RAX using theophylline animal data, which suggests that the NGRA approach for caffeine is sufficiently conservative to protect human health.

  • K.G. Suresh
  • C.T. Jayadeva

It is practical that Major research in the analysis of rolling elements was carried out in the case of one-point defects. For multiple and generalized defect diagnosis, there is a lot of flexibility. The vibration signals for various machines with faulty rolling component bearings are composed & analyzed using vibration signature analysis techniques in this study. Multiple defects on bearing components are used to test the test bearings. The use of vibration signature analysis methods to identify faults in rolling aspect bearings by means of time & frequency domain procedures is investigated in order to determine the best method for fault discovery in the case of several faults in bearing machinery. The feature extracted in this study is expected to be useful in the development of automated fault diagnostics systems for bearing components with multiple defects. In This work we have applied vibration signature analyses on the ball bearings of coffee processing machines and evaluated the results.

The extraction process is a crucial part of the synthesis of Molecularly Imprinted Polymers (MIP). The process will have a significant impact on the number of its cavities that affects the polymers' ability to recognize targets with the same physical and chemical properties as the analytes. Caffeine polymers have been prepared by the cooling-heating method using methacrylic acid (MAA) as a monomer, ethylene glycol dimethacrylate (EDMA) as a crosslinker, benzoyl peroxide (BPO) as an initiator, and chloroform as a solvent. The resulting caffeine polymer powder was extracted using chloroform, methanol / acetic acid (1:20), and methanol, respectively. Finally, the polymer powder is washed using the aquabidest, which is heated at 60°C. The results of FTIR, XRD, and SEM characterization showed that caffeine concentration was significantly reduced. The number of cavities obtained from caffeine MIP is 604 more than before extracted, which is 132 pieces.

  • Ilkay Yilmaz Ilkay Yilmaz
  • Arda Er

Metabolomics, can be defined as little molecule -omics. Nowadays, the elucidation of the molecular mechanism of any disease with genome analysis and proteome analysis is not sufficient. Instead of these, a holistic assessment including metabolomic studies provides rational and accurate results. The application of metabolomics includes the identification of biomarkers, enzyme-substract interactions, drug-activity studies, metabolic pathway analysis and some other studies related with the system biology. Metabolomics is the cheap and correct separation, definition and measurement of all metabolites in cells, tissues or biological fluids in short amounts of time with high throughput technologies such as NMR, GC-MS and LC-MS. It is the quantitative measurement of the metabolic profile of the living being to characterize the genetics and the phenotypic response to nutritional status of it. Data comprehensive approach with the ability to collect high volume quantities, aims to improve our understanding of health and disease, nutrition and food role. The aim of this review; is to emphasize some potential applications of metabolomics in food and nutrition research, to investigate the effects of metabolomics on nutrition and to present scientific literature on these subjects. Keywords : Metabolomics, food, nutrition

  • P Nawrot
  • S Jordan
  • J Eastwood
  • Mark Feeley Mark Feeley

Caffeine is probably the most frequently ingested pharmacologically active substance in the world. It is found in common beverages (coffee, tea, soft drinks), in products containing cocoa or chocolate, and in medications. Because of its wide consumption at different levels by most segments of the population, the public and the scientific community have expressed interest in the potential for caffeine to produce adverse effects on human health. The possibility that caffeine ingestion adversely affects human health was investigated based on reviews of (primarily) published human studies obtained through a comprehensive literature search. Based on the data reviewed, it is concluded that for the healthy adult population, moderate daily caffeine intake at a dose level up to 400 mg day(-1) (equivalent to 6 mg kg(-1) body weight day(-1) in a 65-kg person) is not associated with adverse effects such as general toxicity, cardiovascular effects, effects on bone status and calcium balance (with consumption of adequate calcium), changes in adult behaviour, increased incidence of cancer and effects on male fertility. The data also show that reproductive-aged women and children are 'at risk' subgroups who may require specific advice on moderating their caffeine intake. Based on available evidence, it is suggested that reproductive-aged women should consume </=300 mg caffeine per day (equivalent to 4.6 mg kg(-1) bw day(-1) for a 65-kg person) while children should consume </=2.5 mg kg(-1) bw day(-1).

  • Linda K Massey Linda K Massey

Urinary calcium excretion is strongly related to net renal acid excretion. The catabolism of dietary protein generates ammonium ion and sulfates from sulfur-containing amino acids. Bone citrate and carbonate are mobilized to neutralize these acids, so urinary calcium increases when dietary protein increases. Common plant proteins such as soy, corn, wheat and rice have similar total S per g of protein as eggs, milk and muscle from meat, poultry and fish. Therefore increasing intake of purified proteins from either animal or plant sources similarly increases urinary calcium. The effects of a protein on urinary calcium and bone metabolism are modified by other nutrients found in that protein food source. For example, the high amount of calcium in milk compensates for urinary calcium losses generated by milk protein. Similarly, the high potassium levels of plant protein foods, such as legumes and grains, will decrease urinary calcium. The hypocalciuric effect of the high phosphate associated with the amino acids of meat at least partially offsets the hypercalciuric effect of the protein. Other food and dietary constituents such as vitamin D, isoflavones in soy, caffeine and added salt also have effects on bone health. Many of these other components are considered in the potential renal acid load of a food or diet, which predicts its effect on urinary acid and thus calcium. "Excess" dietary protein from either animal or plant proteins may be detrimental to bone health, but its effect will be modified by other nutrients in the food and total diet.

In this paper the association between smoking history, beverage consumption, diet and bladder cancer incidence is systematically reviewed. A rating system has been used to summarise the level of scientific evidence (i.e. convincing, probable, possible, and no evidence) and the level of association (i.e. substantially increased, (RR> or =2.5), moderately increased (1.5< or =RR<2.5), slightly increased (1.2< or =RR<1.5), no association (0.8< or =RR<1.2), slightly decreased (0.7< or =RR<0.8), moderately decreased (0.4< or =RR<0.7), and substantially decreased (RR<0.4)). There is convincing evidence that cigarette smoking status, frequency and duration substantially increase the risk of bladder cancer. However, the evidence is not clear for other forms of smoking. A small increased risk for cigar, pipe, and environmental smoking is only possible. There is possible evidence that total fluid intake is not associated with bladder cancer. Although there is convincing evidence for a positive association between alcohol consumption and bladder cancer risk in men, the risk is small and not clinically relevant. Coffee and tea consumption are probably not associated with bladder cancer. The authors conclude that total fruit consumption is probably associated with a small decrease in risk. There is probably no association between total vegetable intake, vitamin A intake, vitamin C intake and bladder cancer and a possibly moderate inverse association with vitamin E intake. Folate is possibly not associated with bladder cancer. There probably is a moderate inverse association between selenium intake and bladder cancer risk.

  • Linda K Massey Linda K Massey

Urinary calcium excretion is strongly related to net renal acid excretion. The catabolism of dietary protein generates ammonium ion and sulfates from sulfur-containing amino acids. Bone citrate and carbonate are mobilized to neutralize these acids, so urinary calcium increases when dietary protein increases. Common plant proteins such as soy, corn, wheat and rice have similar total S per g of protein as eggs, milk and muscle from meat, poultry and fish. Therefore increasing intake of purified proteins from either animal or plant sources similarly increases urinary calcium. The effects of a protein on urinary calcium and bone metabolism are modified by other nutrients found in that protein food source. For example, the high amount of calcium in milk compensates for urinary calcium losses generated by milk protein. Similarly, the high potassium levels of plant protein foods, such as legumes and grains, will decrease urinary calcium. The hypocalciuric effect of the high phosphate associated with the amino acids of meat at least partially offsets the hypercalciuric effect of the protein. Other food and dietary constituents such as vitamin D, isoflavones in soy, caffeine and added salt also have effects on bone health. Many of these other components are considered in the potential renal acid load of a food or diet, which predicts its effect on urinary acid and thus calcium. "Excess" dietary protein from either animal or plant proteins may be detrimental to bone health, but its effect will be modified by other nutrients in the food and total diet.

  • Alessandra Tavani
  • C La Vecchia

Epidemiological studies on the relation between coffee consumption and cancer risk have been mainly focused on cancers of the urinary bladder, pancreas and colorectum. The relation between coffee and bladder cancer is controversial, despite a large number of studies published over the last three decades. In most studies, the risk tends to be higher in coffee drinkers than in those who do not drink coffee, but the excess risk is generally moderate and is neither dose- nor duration-related. Thus, a strong association between coffee drinking and bladder cancer can be excluded, although it is still unclear whether the weak association is causal or nonspecific and due to some bias or confounding. For pancreatic cancer, a possible association with coffee consumption has been postulated in a large case-control study published in 1981; since then, however, most studies have shown no substantial association, and overall evidence suggests that coffee is not materially related to pancreatic cancer risk. Overall evidence on the coffee-colorectal cancer relation suggests an inverse association, since most case-control studies found odds ratios below unity, particularly for colon cancer. The pattern of risk is less clear for cohort studies. A plausible biological explanation has been given in terms of coffee-related reduction of bile acids and neutral sterol secretion in the colon. For other cancer sites, including oral cavity, oesophagus, stomach, liver, breast, ovary, kidney and lymphoid neoplasms, the relation of coffee drinking with cancer risk has been less extensively investigated, but the evidence is largely reassuring.

  • Mildred S Christian
  • Robert L. Brent

Caffeine is a methylated xanthine that acts as a mild central nervous system stimulant. It is present in many beverages, including coffee, tea, and colas, as well as chocolate. Caffeine constitutes 1-2% of roasted coffee beans, 3.5% of fresh tea leaves, and approximately 2% of mate leaves (Spiller, '84; Graham, '84a,b). Many over-the-counter medications, such as cold and allergy tablets, headache medicines, diuretics, and stimulants also contain caffeine, although they lead to relatively minimal intake (FDA, '86). In epidemiological studies, it is assumed that one cup of coffee contains < or =100 mg of caffeine, and soft drinks, such as colas, contain 10-50 mg of caffeine per 12-ounce serving. The per-capita consumption of caffeine from all sources is estimated to be about 3-7 mg/kg per day, or approximately 200 mg/day (Barone and Roberts, '96). Consumption of caffeinated beverages during pregnancy is quite common (Hill et al., '77) and is estimated to be approximately 144 mg/day, or 2.4 mg/kg for a 60-kg human (Morris and Weinstein, '81). However, pregnant women appear to consume slightly less than do other adults, approximately 1 mg/kg per day (Barone and Roberts, '96). This decrease may be interrelated with taste aversion (Hook, '76; Little, '82). The medical literature contains many varied references that appear to indicate that human adverse reproductive/developmental effects are produced by caffeine. If caffeine indeed causes such effects, the reproductive consequences could be very serious because caffeine-containing foods and beverages are consumed by most of the human populations of the world, and consumption in the United States is estimated to be 4.5-kg/person/year (Narod et al., '91). Therefore, the medical literature dealing with developmental and reproductive risks of caffeine was reviewed, and the biological plausibility of the epidemiological and animal findings, as well as the methods and conclusions of previous investigators, were evaluated. The epidemiological studies describe exposures of women to caffeine during pregnancy, as well as the occurrence of congenital malformations, fetal growth retardation, small-for-date babies, miscarriages (spontaneous abortions), behavioral effects, and maternal fertility problems that presumably resulted from the caffeine consumption. A few epidemiological studies were concerned with the genetic effects of preconception exposures to caffeine. Animal studies, conducted mostly in pregnant rats and mice, were designed to produce malformations. The objectives of the present review are to summarize the findings from the various clinical and animals studies, objectively discuss the merits and/or faults inherent in the studies and establish a global reproductive risk assessment for caffeine consumption in humans during pregnancy. It should be noted that evaluation of the developmental risks of caffeine based solely on epidemiological studies is difficult because the findings are inconsistent. Even more important, is the fact that caffeine users are subject to multiple confounding factors that make analyses difficult and prevent investigators from reaching definitive conclusions. For example, the caffeine content of foods and beverages can vary considerably, which can interfere with obtaining valid interpretations from many human studies. Isolated epidemiological studies dealing with the risk of abortion, without evaluating other developmental and reproductive effects, are the most difficult to interpret, because they present special problems that are sometimes ignored in epidemiological studies. The results of animal studies are probably most helpful in solving some of the dilemmas created by the epidemiological studies. An animal study reported in 1960 first focused our attention on the potential developmental effects of caffeine. However, the exposure reported by Nishimura and Nakai ('60) was an intraperitoneal dosage of 250 mg/kg in the mouse, an extremely high dosage that would result in a blood plasma level that could never be obtained from consuming caffeine containing products. More recent animal studies have demonstrated, that depending on the method of administration and species, the developmental NOEL in rodents is approximately 30 mg/kg per day, the teratogenic NOEL is 8,100 mg/kg per day, and the reproductive NOEL approximately 80-120 mg/kg per day. Lack of biological plausibility to support the concept that caffeine has been responsible for human malformations is another important part of this analysis. For example, no one has described the Caffeine "teratogenic syndrome," a cluster of malformations associated with caffeine ingestion. Proven human teratogens have an identifiable syndrome. The malformations described in the animal studies at very high doses fit the description of vascular disruptive types of malformations. (ABSTRACT TRUNCATED)

  • Alan Leviton Alan Leviton
  • L D Cowan

From this detailed review of the literature, several conclusions can be drawn: (a) An association between caffeine consumption and a reproductive hazard is more likely to be seen in lower-quality studies than in studies that come closer to approximating the ideal. This is especially evident for "lower" birthweight and congenital anomalies. (b) The association between caffeine consumption and spontaneous abortion may well reflect the Stein-Susser epiphenomenon (women with prominent nausea tend to reduce caffeine consumption and nausea appears to be a marker of good implantation, perhaps reflecting a favorable balance of hormones produced by a healthy placenta). (c) The claim that caffeine consumption by women delays conception has not been followed by convincing support. (d) Reproductive hazards associated with cigarette smoking tend to be associated with caffeine/coffee consumption. Sometimes this appears to be a consequence of residual confounding associated with inadequate adjustment for cigarette smoking, which is over-represented among those who drink the most coffee/caffeine. Sometimes this reflects the tendency of women to underreport socially undesirable behaviors (e.g. smoking) while accurately reporting socially neutral behaviors (e.g. coffee and caffeine consumption). Thus, it seems reasonable to conclude that no convincing evidence has been presented to show that caffeine consumption increases the risk of any reproductive adversity.

  • Eduardo Salazar-Martínez
  • Walter C Willett Walter C Willett
  • Alberto Ascherio
  • Frank B Hu

In small, short-term studies, acute administration of caffeine decreases insulin sensitivity and impairs glucose tolerance. To examine the long-term relationship between consumption of coffee and other caffeinated beverages and incidence of type 2 diabetes mellitus. Prospective cohort study. The Nurses' Health Study and Health Professionals' Follow-up Study. The authors followed 41 934 men from 1986 to 1998 and 84 276 women from 1980 to 1998. These participants did not have diabetes, cancer, or cardiovascular disease at baseline. Coffee consumption was assessed every 2 to 4 years through validated questionnaires. The authors documented 1333 new cases of type 2 diabetes in men and 4085 new cases in women. The authors found an inverse association between coffee intake and type 2 diabetes after adjustment for age, body mass index, and other risk factors. The multivariate relative risks for diabetes according to regular coffee consumption categories (0, <1, 1 to 3, 4 to 5, or > or =6 cups per day) in men were 1.00, 0.98, 0.93, 0.71, and 0.46 (95% CI, 0.26 to 0.82; P = 0.007 for trend), respectively. The corresponding multivariate relative risks in women were 1.00, 1.16, 0.99, 0.70, and 0.71 (CI, 0.56 to 0.89; P < 0.001 for trend), respectively. For decaffeinated coffee, the multivariate relative risks comparing persons who drank 4 cups or more per day with nondrinkers were 0.74 (CI, 0.48 to 1.12) for men and 0.85 (CI, 0.61 to 1.17) for women. Total caffeine intake from coffee and other sources was associated with a statistically significantly lower risk for diabetes in both men and women. These data suggest that long-term coffee consumption is associated with a statistically significantly lower risk for type 2 diabetes.