Newsletters

December 2009

Trans fats increase sudden deaths
Soy improves breast cancer survival
Soy lowers gynecological cancers
Phytoestrogens not a cancer risk
Exercise helps telomeres, slows aging
Vitamin B6 reduces heart attacks

Trans fats increase sudden deaths

Higher levels of trans fat intake are associated with an increased risk of sudden deaths in women (and probably men, but this study was of women only). In this prospective analysis of trans fat intake and sudden cardiac deaths among 86,762 women in the Nurses’ Health study, the subjects were followed for 26 years starting in 1980. (Chiuve SE, et al., Intake of total trans, trans-18:1, and trans-18:2 fatty acids and risk of sudden cardiac death in women. Am Heart J. 2009 Nov;158(5):761-7.)

While there was no apparent association for the entire group, among women who had previously been diagnosed with heart disease, those with the highest trans fat intake had triple the risk of sudden death compared to those with the lowest  intake. Although the risk for the whole group was increased by 28 percent, this was not statistically significant.

Trans fats are produced when polyunsaturated oils are hydrogenated to produce shortening and margarine. They are virtually non-existent in unprocessed, natural foods, but they have infiltrated the diet because of the large quantity of fast-food fats in the American food supply. Fortunately, trans fats are gradually being reduced in these foods (even though they remain unhealthy for many other reasons, such as too much fat overall, too much salt, too many calories, and many artificial ingredients.

Soy improves breast cancer survival

Rumors are abundant about the supposed dangers of consuming soy foods. The scientific literature simply does not support them. Consuming soy foods (such as tofu, tempeh, and soy milk, not the highly processed texturized soy protein) has many advantages for health, as is evident from the low rates of a variety of diseases among populations who do consume them. Several recent studies confirm some of these benefits.

In one report, the Shanghai Breast Cancer Survival Study, 5042 women breast cancer survivors, aged 20 to 75 years, were followed through June of 2009. They were evaluated at 18, 36, and 60 months for an average follow-up of 3.9 years. (Shu XO, et al., Soy food intake and breast cancer survival. JAMA. 2009 Dec 9;302(22):2437-43.)

Researchers assessed their consumption of soy foods by measuring either soy proteins or soy isoflavones in the diet and related it to breast cancer recurrence or death. Those women with the highest soy intake had a 29 percent lower risk of mortality, and a 32 percent lower risk of recurrence of their breast cancer than those with the lowest consumption., This was seen in both estrogen receptor-positive or –negative tumors and in both users and nonusers of tamoxifen. Because the population was relatively homogeneous, these results cannot be ascribed to genetics.

Soy lowers gynecological cancers

Investigators did a meta-analysis of studies relating soy intake to ovarian and endometrial cancer, including case control studies and cohort studies. They included seven studies in their analysis that met their criteria for inclusion. (Myung SK, et al., Soy intake and risk of endocrine-related gynaecological cancer: a meta-analysis. BJOG. 2009 Dec;116(13):1697-705.)

When they combined the results of all the studies, among those women with the highest soy intake, the risk of endometrial cancer was 30 percent lower than among those with the lowest soy intake. For ovarian cancer the risk was lowered by 48 percent.

Of course, a meta-analysis is limited by the quality and quantity of available data, and it is not a prospective or interventional study, but it does confirm the results seen in other studies, and the biochemical and physiological bases for the results.

Phytoestrogens not a cancer risk

Soy foods are among the many sources of phytoestrogens in the diet. Other sources are vegetables, fruits, nuts, seeds, and grains. Some sources of phytoestrogens in soy are the isoflavones genistein and daidzein. Other main sources of phytoestrogens are the lignans found in seeds, particularly flax seeds. Because they have some estrogenic effects, some people mistakenly think they might cause the same problems that have been linked with hormone replacement therapy (with horse-derived estrogens).

In fact, plant-based estrogens appear to reduce the potential harm from stronger estrogens. A new study from England shows that a high intake of phytoestrogens does not have a significant effect on the risk of breast, colorectal, and prostate cancers, as has been suggested because of their weak estrogenic effects. (Ward HA, Breast, colorectal, and prostate cancer risk in the European Prospective Investigation into Cancer and Nutrition-Norfolk in relation to phytoestrogen intake derived from an improved database. Am J Clin Nutr. [Epub ahead of print].

The only significant association in the 25,000 adults who were studied was a decrease in women of the risk of colorectal cancer associated with a higher intake of enterolactones (from grains) and enterolignans (from seeds, such as flax seeds), both of which led to a nearly 80 percent risk reduction.

Exercise helps telomeres, slows aging

Telomeres are the DNA molecules that serve as the “end caps” of chromosomes, and they protect the integrity of the chromosome during cell division. They have been described as being like the “plastic tips on the ends of shoelaces” that protect them from fraying. As chromosomes divide, the telomeres get shorter and shorter, and eventually the cell division process fails, leading to many of the signs of aging. These include loss of muscle strength, wrinkling of the skin, and a decline in vision and hearing. It also leads to chronic degenerative diseases.

An enzyme called telomerase protects the telomeres from deterioration. Telomerase adds gene sequences to the chromosomal DNA ends, preserving telomere length. A decline in telomerase activity has been linked to a higher risk of heart disease and increased levels of cardiac risk factors as well as the above age-related disorders. Obesity and insulin resistance reduce telomerase activity, likely contributing to an increased risk of heart disease.
Several recent studies show the benefits of exercise and lifestyle to protect telomeres. One study shows that regular endurance exercise helps to preserve telomere length. Researchers examined the white blood cells in 32 young athletes and 25 aged athletes and compared them to the cells in age-matched controls who did little exercise. (Werner C, et al., Abstract 1380: Beneficial Effects of Long-term Endurance Exercise on Leukocyte Telomere Biology. Circulation. 2009;120:S492.)

In both of the exercise groups the activity of telomerase was greatly enhanced. In the older athletes, telomere length was over 80 percent greater than in sedentary subjects, while in young athletes the lengths were the same as in the young controls, even with higher telomerase activity (remember that telomere length declines with age, so the young controls had normal telomere length even in the absence of exercise.) Aging eliminates this advantage.

In a related study, mice were given a running wheel in their cages, while a control group was not, and their white blood cells and aortic wall cells were evaluated after three weeks. (Werner C, et al., Physical exercise prevents cellular senescence in circulating leukocytes and in the vessel wall. Circulation. 2009 Dec 15;120(24): 2438-47.)

The mice that were given the exercise wheel had increased telomerase activity in both their aortic wall cells and in their white blood cells. The exercising mice also had less aortic cell apoptosis (programmed cell death) than the controls and better activity of enzymes and proteins that help protect both telomeres and cells from the stress induced by exercise.

An earlier study showed the benefits of a comprehensive lifestyle change for protecting telomeres and preventing disease. Researchers noted that shortening telomeres are associated with premature mortality from many types of cancer as well as heart disease. They evaluated 30 men with biopsy-diagnosed prostate cancer and placed them on a comprehensive lifestyle program including moderate aerobic exercise, diet, and stress reduction, plus dietary supplements. (Ornish D, et al., Increased telomerase activity and comprehensive lifestyle changes: a pilot study. Lancet Oncol. 2008 Nov;9(11):1048-57.)

Within three months, telomerase activity in their white blood cells increased by over 25 percent. The program included walking for 30 minutes and one hour of relaxation six days a week, a low-fat diet based on vegetables, fruits, whole grains, and beans, a daily serving of tofu, and supplements of three grams of fish oil, vitamins C and E, and selenium. This shows that you can have a great influence on chronic disease and aging through lifestyle choices.

Vitamin B6 reduces heart attacks

Pyridoxine is the primary form of vitamin B6 in the diet. In the body it is converted to pyridoxal 5-phosphate (P5P). A high level of P5P in the blood plasma is associated with a lowered risk of heart attacks in women. Researchers took blood samples from 32,826 women, measuring P5P levels. (Page JH, et al., Plasma vitamin B(6) and risk of myocardial infarction in women. Circulation. 2009 Aug 25;120(8):649-55.)

Over nine years, 239 of the women had heart attacks, either fatal or non-fatal. These subjects were matched with controls by age, smoking status, and other related parameters. Those women with the highest plasma levels of P5P had a 78 percent reduction in heart attacks compared to those with the lowest levels. Plasma P5P is influenced by diet, absorption, metabolism, and excretion rates (stress increases excretion).

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Information herein is not medical advice or direction. All material in this newsletter is provided for information only. Its contents should not be used to provide medical advice on individual problems. Consult a health care professional for medical or health advice.

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