Getting More from Vitamins and Minerals

Of the many nutraceuticals that fortify functional foods and dietary supplements, vitamins and minerals boast both a long history of usage and government dietary recommendations. Past research has proven the necessity of specific vitamins and minerals in human nutrition. Consequently, it is no surprise that half of all American adults take vitamin or mineral supplements each day, according to a 2000 national public opinion survey by the American Dietetic Association (ADA).

Available not only as multivitamins and individual supplements, vitamins and minerals also fortify a multitude of products, from infant formulas and children’s snacks to beverages and meal replacements. Vitamin and mineral supplementation is even being tailored to individual needs. For example, Nutrophy, a Florida-based company, has its customers fill out an online questionnaire at www.nutrophy.com. Based on their answers, the company recommends a supplement regimen based on their unique profile.

Because of the wide availability of vitamins and minerals, it is rare that deficiencies would exist in the United States and other developed countries. “When it comes to supplementing these nutrients, it is more a matter of what consumers are not taking,” said ADA spokesperson Jackie Berning, Assistant Professor of Biology at the University of Colorado, Colorado Springs. “You’ll see sales go up for certain vitamins or minerals whenever there is a lot of publicity or hype about their health benefits. Right now, it seems that antioxidants, like vitamin E and selenium, are hot. Consumers are taking these to benefit their whole lifestyle and prevent diseases as they age, such as macular degeneration, heart disease, and cancer.”

Here is a brief listing of some vitamins and minerals and recent studies that support their additional health benefits.

Vitamin D
Vitamin D is already known to be vital for bone health. However, a recent study suggested that it may be more useful than calcium in protecting older women from fractures associated with osteoporosis (Feskanich et al., 2003). Researchers at the Brigham and Women’s Hospital and the Harvard Medical School, Boston, assessed relations between postmenopausal hip fracture risk and calcium, vitamin D, and milk consumption.

In this 18-year analysis of 72,337 postmenopausal women, dietary intake and nutritional supplement use were assessed at baseline in 1980 and updated several times during followup. Women consuming 12.5 μg or more of vitamin D per day from food plus supplements had a 37% lower risk of hip fracture than did women consuming less than 3.5 μg/day. In addition, the risk of hip fracture was not influenced by the amount of calcium intake from milk or supplements in these women.

The researchers concluded that “Because women commonly consume less than the recommended intake of vitamin D, supplement use or dark fish consumption may be prudent.”

Acknowledging vitamin D’s role in bone health, The Minute Maid Co., an operating group of The Coca-Cola Co., rolled out Minute Maid® Premium Orange Juice fortified with vitamin D in April 2003. This past February, the Food and Drug Administration issued a regulation allowing the addition of vitamin D to calcium-fortified juices. An 8-fl-oz serving of Minute Maid juice now provides 25% of the recommended daily amount of vitamin D and 35% of the recommended daily amount of calcium.

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Vitamin E
Last month’s Nutraceuticals & Functional Foods column discussed vitamin E’s relationship with Alzheimer’s disease and memory. A recent preliminary study suggested that foods rich in vitamin E may prevent Parkinson’s disease, a disease of the nervous system (Zhang et al., 2002).

Researchers in Harvard School of Public Health’s Dept. of Nutrition analyzed the dietary habits of 371 diagnosed cases of Parkinson’s disease among 76,890 women in the Nurses’ Health Study and 47,331 men in the Health Professionals Follow-Up Study. The women were tracked for 14 years, and the men for 12 years.

The risk of Parkinson’s disease was significantly reduced among men and women with high intake of dietary vitamin E from foods only. Neither intake of total vitamins E or C nor use of vitamin E or vitamin C supplements or multivitamins was significantly associated with risk of Parkinson’s disease.

The researchers concluded that the reduction in risk suggests that other constituents of foods rich in vitamin E may be protective. They added that “Alternatively, moderate amounts of vitamin E may reduce risk of Parkinson’s Disease, but this benefit may be lost with higher intakes.”

Another study explained a possible reason for vitamin E’s protective role in heart disease (Desideri et al., 2002). Researchers in the Dept. of Internal Medicine and Public Health at the University of L’Aquila, Blocco, Italy, asked 39 healthy men in their 30s and 40s to take 50 International Units of vitamin E or placebo daily for 20 weeks. The study aimed to evaluate whether a low dose of vitamin E (α-tocopherol) affected the adhesion molecule, ICAM-1, in healthy subjects. According to the authors, up-regulation of ICAM-1 at the vascular endothelial level is one of the most important promoters in the slow progression of a healthy vessel to an atherosclerotic one.

After 20 weeks of vitamin E supplementation, the men’s levels of ICAM-1 declined by almost 12%. The researchers regarded this as a significant decrease following supplementation with a low dosage of vitamin E. ICAM-1 concentrations were stable in healthy subjects over a period of 20 weeks, while they significantly decreased with low dose of α-tocopherol. The authors concluded that antioxidant vitamins are likely to counteract with endothelial changes that could potentially trigger the atherogenetic process.

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Vitamin C
In addition to vitamin E, vitamin C is also thought to help reduce the risk of age-related mental impairment. A team of researchers from the U.S. Dept. of Agriculture’s Human Nutrition Research Center at Tufts University reviewed 197 scientific papers on the causes of cognitive impairment and relevant studies of antioxidants (Martin et al., 2002). They noted that inflammatory processes and vascular dysfunctions appear to play important roles in the pathogenesis of age-associated pathologies, including Alzheimer’s and Parkinson’s disease. The authors stated that a large body of evidence showed that both vitamins E and C are important for the central nervous system and that a decrease in their concentrations causes structural and functional damage to the cells. They added that several studies revealed a link between diets rich in fruits and vegetables containing generous amounts of vitamins E and C and lower incidence of certain chronic diseases.

Reuters Health reported in February that women who added extra vitamin C to their diet during pregnancy lowered their risk of premature delivery, according to a team of researchers at the National Institute of Perinatology in Mexico City (Huggins, 2003).

Lead researcher Veronica Gutierrez told Reuters Health that in Mexico, premature rupture of the membrane surrounding the fetus has become relatively common among pregnant women. This rupture can increase a woman’s risk of premature delivery.

Vitamin C is known to play an important role in the structure of the collagen-composed membrane. Gutierrez and her colleagues speculated that supplementing pregnant women’s diets with vitamin C would prevent levels from the nutrient in white blood cells, where it is stored, from dropping.

Their findings were presented during the American Society for Parenteral and Enteral Nutrition’s annual meeting. For the study, 52 women in their fifth month of pregnancy were given either a placebo or 100 mg of vitamin C each day for three months.

As is typical during normal pregnancy, vitamin C levels in blood plasma decreased for all the women. However, the white blood cell concentration of the vitamin decreased only among women given the placebo.

Additionally, women who took vitamin C supplements experienced an increase in their white blood cell concentration of the vitamin, noted Gutierrez. At delivery, less than 5% of the women who received vitamin C supplements experienced premature membrane rupture, in comparison to nearly 25% of women taking the placebo.

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The researchers concluded that vitamin C supplementation maintains stores of the nutrient in white blood cells and “may have value in preventing premature rupture.”

Commenting on the study, Anna Siega-Riz, Assistant Professor in the Dept. of Maternal and Child Health at the University of North Carolina at Chapel Hill, said it “contributes another piece of evidence that vitamin C is important in the events that lead to premature rupture of the membranes.” Siega-Riz was not involved in the current study but has performed research linking vitamin C deficiency with premature rupture.

The difference in membrane rupture rates between the two study groups “suggests that more studies with ample power to detect a difference are needed to confirm the role of vitamin C in preventing premature rupture,” Siega-Riz told Reuters Health.

Still, in light of Gutierrez’s findings, and her own research, Siega-Riz said, “it is only prudent to develop vitamin C recommendations for pregnant women.”

Gutierrez noted that the extra vitamin C should not just come in the form of pills. Pregnant women should also be sure to eat lots of vitamin C–containing fruits and vegetables, such as citrus fruits and broccoli, she said.

Vitamin K
A team from the USDA Human Nutrition Research Center on Aging at Tufts University, Boston, showed that women with a low vitamin K intake may be at increased risk of bone fractures (Booth et al., 2003). The researchers studied self-reported dietary vitamin K intake and measured bone mineral density (BMD) of the hip and spine in more than 1,100 men and almost 1,500 women 29–86 years old.

Dietary and supplemental intakes of vitamin K were assessed with the use of a food-frequency questionnaire. The researchers also accounted for such factors as age, body mass index, smoking status, alcohol use, physical activity score, and menopause status and current estrogen use among the women.

Women with the lowest vitamin K intake (around 70.2 μg/day) had significantly lower mean BMD than those with the highest intake of vitamin K (around 309 μg/ day). These associations remained after controlling for variables and after stratification by age or supplement use. However, no significant association was found between dietary vitamin K intake and BMD in men.

The authors concluded that “Low dietary vitamin K intake was associated with low BMD in women, consistent with previous reports that low dietary vitamin K intake is associated with an increased risk of hip fracture. In contrast, there was no association between dietary vitamin K intake and BMD in men.”

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Selenium 
Some studies suggest that selenium may help prevent cancer and possibly heart disease. In early 2002, USDA’s Agricultural Research Service launched a study to research moderately high doses of selenium and their effects on human cardiovascular health, immune function, and reproductive health (Wood, 2002). More than 30 healthy men aged 18–45 are participating in the study. For one year, half the volunteers will take a daily capsule providing five and one-half times the recommended dietary allowance of selenium in the form of high-selenium yeast. The other half will receive a daily placebo—a capsule containing only yeast and no selenium. Samples of blood, urine, semen, and other specimens will be provided for laboratory tests at regular intervals. Participants will also receive tests for cardiovascular function and several other health indicators. In addition, they will complete detailed records of their exercise, general health, and the foods they have eaten during specific 3-day periods. It is hoped that the project, already in its second phase, will provide new, detailed information about selenium.  

In a study at Purdue University in West Lafayette, Ind., dogs fed a diet supplemented with selenium had a lower level of DNA damage in their prostate compared to dogs fed an unsupplemented diet (Waters et al., 2003).

Researchers randomly assigned 49 elderly male dogs to a normal diet or one of four diets supplemented with different amounts of selenium. After seven months, the prostates of dogs fed diets supplemented with selenium had less DNA damage than those of dogs fed the normal diet. Also, compared to dogs on the normal diet, dogs fed the supplemented diet had twice the number of prostate cells that had undergone apoptosis, a mechanism that can remove damaged cells.

The authors concluded that “selenium may benefit the aging prostate by decreasing the accumulation of DNA damage in epithelial cells even before these cells show cytotoxic changes suggestive of malignancy.” The authors did not relate the study to developments in humans, but the trace mineral, present naturally in nuts, vegetables, and whole grains, has been shown to inhibit cancer development in a variety of experimental animal models.

Diet vs Individual Nutrient Supplementation
It is important to keep in mind that the studies mentioned above are preliminary and do not suggest individual nutrient supplementation. “I always promote nutrient density when it comes to diets,” said Berning. “Picking fruits, vegetables, whole grains, rice, pastas, and lean meats creates a balanced diet that provides all essential vitamins and minerals. There are 40 known nutrients, and not one food can give you all 40.”

Yogurt Smoothie Targets Women’s Health
A survey conducted by Yoplait® asked more than 1,000 American women age 25–55 about their personal eating and nutrition habits. The results:
37% of the respondents skipped one meal per day on most days; on average, those surveyed skipped 4.5 meals every week; 67% skipped breakfast; and 22% skipped lunch; only 32% claimed they were certain they received at least 1,000–1,200 mg of calcium per day.

Responding to women’s health concerns, Yoplait is introducing Yoplait® Nouriche™ nationwide in mid- April. Nouriche is a nonfat yogurt smoothie that offers a mealtime solution packed with 20 vitamins and minerals, including vitamins A and C, calcium, iron, riboflavin, phosphorus, and magnesium. The smoothie offers at least 25% of the daily value (DV) of 17 vitamins and minerals, including 30% of the DV for calcium. It also provides 20% of the DV for protein (10 g) and 22% of the DV of fiber (6 g). It will be available in four flavors:
strawberry, peach, raspberry, and tropical.

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Scenarios for Supplementing
Although over-nutrition is more of a problem than under-nutrition in the U.S., there are certain groups of people who are at more risk of not getting enough vitamins or minerals. In 1998, the Food and Nutrition Board of the National Academy of Sciences recommended fortified or supplemental nutrient sources to increase the bioavailability of specific vitamins for certain population groups that have altered absorption or very high nutrient needs. These included vitamin B-12 and folic acid (FNB, 1998).

FNB recommended supplemental vitamin B-12 for strict vegans who eliminate all animal products from their diet; vitamin D for those with limited milk intake and sunlight exposure; calcium supplements and/ or calcium-fortified foods for those with lactose intolerance or allergies to dairy products; and a multivitamin and mineral supplement for those following severely restricted weightloss diets (e.g., <1,200 kcal/day).

Other groups have also been targeted for supplementation:
• Pregnant Women. Research has led to the recommendation that women capable of becoming pregnant obtain 400 μg of synthetic folic acid daily from either fortified foods or a supplement, in addition to consuming food folate from a varied diet.

• Elderly. According to FNB, 10– 30% of persons older than 50 have atrophic gastritis, a condition that reduces the absorption of food-bound vitamin B-12. FNB recommended that this group obtain vitamin B-12 from supplements or fortified foods.

• Fad Dieters. According to the American Dietetic Association, the popular high-protein, low-carbohydrate diets tend to be low in calcium and fiber, as well as healthful phytochemicals. Some authors of these fad diets advise taking vitamin– mineral supplements to replace lost nutrients. However, ADA recommends that supplements should “bridge the gap” in healthy eating and not be used as a replacement for nutrient-rich foods.

by LINDA MILO OHR
Contributing Editor
Chicago, Ill.

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