Soy Infant Formula Given a Clean Bill of Health
First introduced almost 100 years ago, soy infant formula has been in widespread use since the 1960s. It has been estimated that more than 20 million Americans consumed soy infant formula as babies. Despite this long history of use, questions about the safety of soy infant formula have arisen. They are based largely on the high isoflavone content of soybeans.
Isoflavones are commonly classified as phytoestrogens, or plant estrogens. They are, however, very different from the hormone estrogen. Recently, researchers from universities in Belgium, Indonesia and Mexico evaluated the safety of soy infant formula in relation to growth, bone health, immunity, cognition, and reproductive and hormone functions. Their analysis included both population (epidemiologic) and clinical studies that compared soy infant formula with other types of infant formulas or with breast milk.
The investigators found that the height, weight and growth patterns of children fed soy infant formula were similar to those of children fed cow’s milk formula or human milk. In addition, serum hemoglobin, protein, zinc and calcium concentrations and bone mineral content were all found to be similar to those of children fed cow’s milk or breast milk. Immune measurements and neurocognitive parameters were similar in all the feeding groups.
Not surprisingly, the authors of this study concluded that modern soy infant formula is a safe option for infants. This position is identical to that of the American Academy of Pediatrics which has stated that soy infant formula is an effective alternative to human milk or formulas based on cow’s milk.
Finally, these conclusions are similar to those stemming from the Beginnings Study, a study underway at the Arkansas Children’s Nutrition Center (ACNC). The ACNC is studying development, nutritional status, and health of formula-fed children from birth through puberty. While numerous studies have compared the effects soy infant formula, cow’s milk formula, and breast milk on growth, few have followed the effects over such a long developmental period as the Beginnings Study. It’s also the only study to look at body composition and brain development and function by studying behavior, cognition, psychomotor and language development. A recent article by the lead investigator of the Beginnings Study concluded that there is no evidence of the adverse estrogenic effects that originally prompted the debate about soy infant formula, and there is no reason to restrict its use.
Vandenplas Y, Castrellon PG, Rivas R, et al. Safety of soya-based infant formulas in children. Br J Nutr 2014;1-21.
Bean Fiber Protects Against Prostate Cancer
Prostate cancer is the second most common cancer, after skin cancer, in American men. It is estimated that more than 230,000 new cases of prostate cancer will be diagnosed and nearly 30,000 men will die of this disease in 2014. The average age of diagnosis is 66 and one of seven men will develop prostate cancer.
The good news is that, while it can be a serious disease, most men diagnosed with prostate cancer have an excellent prognosis. In fact, more than 2.5 million men in the United States have been diagnosed with prostate cancer at some point in the past.
But while treatment is effective and survival rates are good, prevention remains important. A number of dietary factors, including fiber, may influence the risk of developing prostate cancer. Although high-fiber diets may protect against this disease, French researchers have found that the type and source of fiber may matter. They examined this relationship in a group of 3313 men. Over a 13 year period, during which time the men provided information about their diets, 139 of them were diagnosed with prostate cancer. Those who consumed the most total dietary fiber and insoluble fiber were about 50% less likely to have developed prostate cancer.
Insoluble fiber passes through the gastrointestinal tract relatively intact, and speeds up the passage of food and waste. As a result, it has a laxative effect and can help reduce constipation. Insoluble fibers are mainly found in whole grains and vegetables.
But it turns out that the source of the fiber may have an impact on risk. When the French researchers looked at the relationship of fiber from different foods to risk for prostate cancer, they found that fiber from legumes was very protective whereas there was no benefit to consuming fiber from cereals, vegetables and fruit. Just one-half cup of cooked beans can provide the amount of fiber that was associated with protection against prostate cancer in this study.
Soybeans are one type of legume that may have additional benefits for men’s health. In addition to being high in fiber, they are packed with phytoestrogens. This may be one reason why men in Asia, where soy is a common part of the diet, are only half as likely as western men to develop prostate cancer.
Deschasaux M, Pouchieu C, His M, et al. Dietary total and insoluble fiber intakes are inversely associated with prostate cancer risk. J Nutr 2014