Scientific Update

More than one-third of American adults use vitamin and mineral supplements daily, a marked increase from 23.7 percent in 1992. Supplement users tend to be women and older people, and they tend to live in the West and Northeast. Daily use of vitamins A, C, and E has also increased compared to previous surveys. Calcium use has increased in the past 8 years, with 11 percent of respondents using daily calcium supplements. American adults are also using herbal and botanical supplements more often. About 6 percent of adults in the U.S. use this type of supplement daily; 14.5 percent used an herbal or botanical supplement sometime in the past year.

Millen AE, Dodd KW, Subar AF. 2004.

Use of vitamin, mineral, nonvitamin, and nonmineral supplements in the United States: The 1987, 1992, and 2000 National Health Interview Survey results. J Am Diet Assoc 104:942-50.

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Many Americans Are Not Getting Enough Vitamin D

Vitamin D is an important nutrient for bone health that may also play a role in cancer prevention and treatment. Adequate vitamin D can be produced by our bodies following sunlight exposure. However, factors like sunscreen use, pollution, season of the year, aging, and limited sunlight exposure can make it impossible to meet vitamin D needs without dietary or supplemental sources of vitamin D. Few foods contain naturally occurring vitamin D. Most people rely on fortified foods, including breakfast cereals, soy and rice milks, cow’s milk, juices, and margarine to meet their vitamin D needs. Researchers recently examined vitamin D intakes of various groups in the United States and found that several groups are not getting enough vitamin D. Up to 90 percent of older people do not consume adequate amounts of vitamin D. Female teenagers and young adults also are likely to have low intakes of vitamin D. Vitamin D-fortified foods, such as fortified soy and rice milks, juices, and breakfast cereals, should be used regularly to insure an adequate intake of vitamin D.

Moore C, Murphy MM, Keast DR, Holick MD. 2004.

Vitamin D intake in the United States. J Am Diet Assoc 104:980-83.

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Food Sources of Nutrients

A survey of more than 10,000 adults in the U.S. gives us a look at what foods are providing key nutrients in the American diet. Interesting findings include:

• Bread, beef, sweet baked goods like cookies and cakes, and soft drinks account for more than a quarter of the calories in a typical adult diet.
• Beef provides 10 percent of the fat in a typical adult diet, while cheese provides 7 percent.
• The top sources of saturated fat, accounting for one-third of the saturated fat for a typical adult, are cheese, beef, and cow’s milk.
• Eggs, beef, poultry, and cheese supply more than 60 percent of Americans’ cholesterol.
• Yeast bread and dried beans provides almost one-fourth of the fiber in adults’ diets.
• Although beef is often promoted as an iron source, fortified cereals and yeast bread provide a total of 30 percent of iron, while beef only provided 8.5 percent.
• Fortified breakfast cereals are an important source of folate, thiamin, riboflavin, vitamin B₆, iron, and zinc.

Cotton PA, Subar AF, Friday JE, Cook A. 2004.

Dietary sources of nutrients among US adults, 1994-2011. J Am Diet Assoc 104:921-30.

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An Update on Soy

The 5th International Symposium on the Role of Soy in Preventing and Treating Chronic Disease was held in September 2003. Close to 300 health care professionals and researchers from 20 different countries attended this conference. A full report on the conference can be found in the May 2004 issue of Journal of Nutrition. Interesting findings that were presented include:

• In older Chinese women, higher intakes of soy protein and isoflavones were associated with greater bone density.
• Supplements of isoflavones, calcium, and vitamin D resulted in an increase in bone mineral in Chinese women.
• When breast-feeding women consume soy, soy isoflavones appear in their breast milk and are absorbed by their infants. The significance of this is not known, although researchers speculate that early exposure to soy may protect against chronic disease in adulthood.
• An analysis of a number of studies on soy and hot flashes found that, overall, use of soy products reduced the frequency of hot flashes.
• Isoflavone supplements reduced the severity of headaches and other symptoms of premenstrual syndrome (PMS).
• Soy protein may be useful in reducing risk of prostate cancer because it affects male hormone levels.
• Preliminary results suggest that soy isoflavones can improve brain functions, such as memory in older people.

Messina M, Erdman J Jr, Setchell KDR. 2004.

Fifth International Symposium on the Role of Soy in Preventing and Treating Chronic Disease. J Nutr 134 (Suppl):1205S-2011S.

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Life-Long Vegetarians in Belgium

Most studies of vegetarians examine people who became vegetarian in adulthood. A recent study from Belgium looked at 36 life-long vegetarians between 14 and 71 years old. Subjects’ diets were analyzed, their blood was checked for cholesterol and other parameters, and their physical fitness was assessed. They were also asked about their health. They reported fewer diseases and allergies and lower medication use than the average person in Belgium. Very few vegetarians were smokers or drinkers. The vegetarians tended to have diets that were higher in fat (average of 34.4 percent of calories from fat) and saturated fat (13 percent of calories) and lower in carbohydrate (51 percent of calories) than the usual recommendations. Intakes of thiamin, riboflavin, vitamin A, and vitamin C were usually adequate, although vitamin B₆ intakes were low. Calcium intake was quite low in some subjects, zinc intake was low in most subjects, and iron intake of young women was low. Three subjects had subnormal levels of vitamin B₁₂in their blood. This group of subjects had normal levels of endurance but did not perform well in strength tests. These results suggest that life-long vegetarians in Belgium are generally healthy, but their diets could have been improved by choosing more foods providing calcium, zinc, iron, and vitamins B₆ and B₁₂.

Clarys P, Deriemaeker P, Hebbelinck M, et al. 2004.

Physical fitness and health-related parameters in Flemish life-long vegetarians: a pilot study. Nutr Food Sci 34:29-41.

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What Is Causing the Current Epidemic of Diabetes?

Type 2 diabetes (also called adult-onset diabetes) is occurring at an epidemic rate in the United States. Currently, more than 16 million Americans have type 2 diabetes. Is it possible that the Standard American Diet (SAD) is leading to this epidemic? The evidence suggests that it is. Carbohydrate may be a major player. Carbohydrate sources in our diets include grain products like bread, cereal, pasta, and rice; fruits and vegetables; milk; and sugar from candy, desserts, and soft drinks. Between 1909 and 1963, carbohydrate consumption decreased in the United States, mainly because we weren’t eating as many whole grains. Since 1963, carbohydrate consumption has increased back to 1909 levels, not because we’re eating more whole grains but because we’re eating a lot of sugar.

We’re also eating more calories. In the past 20 years, the average caloric intake in the U.S. has increased by 500 calories per day, mainly because of an increase in carbohydrates, especially carbohydrates from refined sweeteners like corn syrup. In those same 20 years, the prevalence of diabetes and obesity has also markedly increased. Is there a connection? It seems likely that there is. Risk of type 2 diabetes may be reduced by replacing refined carbohydrates (sugar and corn syrup) with whole grains and other high fiber sources of carbohydrate.

Gross LS, Li L, Ford ES, Liu S. 2004.

Increased consumption of refined carbohydrates and the epidemic of type 2 diabetes in the United States: an ecologic assessment. Am J Clin Nutr 79:774-79.