Omega 3 Fatty Acids in Fish Oil Reduce Incidence of Age-related Macular Degeneration

A recent study of a large population of women showed that regular consumption of fish and EPA and DHA (omega-3 fatty acids found in fish) was associated with a significant decrease in the risk of age-related macular degeneration, a major cause of blindness.

Age-related macular degeneration (AMD), a major cause of blindness, is estimated to affect 9 million U.S. adults. Evidence from observational and epidemiologic studies suggest an inverse relation between regular dietary intake of fish and DHA and EPA and the risk of advanced AMD.
In a recent study published online in the Archives of Ophthalmology, researchers examined whether the intake of omega-3 fatty acids and fish affects the incidence of AMD in women.

A detailed food-frequency questionnaire was completed by 38,022 women at an average age of 54.6 years. All women were free of a diagnosis of AMD at the beginning of the trial. After an average of 10 years follow-up, 235 cases of AMD were confirmed.

Women in the highest third of intake of DHA, compared to those in the lowest, had a 38% decreased risk of AMD. Those with the highest third of intake of EPA had a 34% decrease risk of AMD. Similarly to intakes of individual omega-3 fatty acids, women who consumed 1 or more servings of fish per week had a 42% decreased risk in comparison to those who ate less than 1 serving per month.

The results from this prospective study from a large population of women indicate that regular consumption of fish and omega-3 fatty acids from fish (EPA and DHA) significantly reduces the risk of AMD. This is some of the strongest evidence to date that support a role for long-chain fatty omega-3 fatty acids in the primary prevention of AMD, and possibly a reduction in the number of people who ultimately have advanced AMD, potentially leading to blindness.

William G. Christen, ScD et al. Dietary omega Fatty Acid and Fish Intake and Incident Age-Related Macular Degeneration in Women. Arch Ophthalmol. Published online March 14, 2011. doi:10.1001/archophthalmol.2011.34

Dietary Zinc Reduces Risk of Death From Prostate Cancer

According to a new Swedish study, men with a higher intake of dietary zinc may reduce the risk of prostate-related death.

The mineral zinc is involved in numerous enzymes and many essential cellular functions, including health of the immune system and DNA repair. Although previous research supports a role for zinc in prostate carcinogenesis, epidemiologic data are currently inconsistent. Little to no data on cancer-specific survival and zinc intake has been reported.

In a recent study, researchers sought to determine whether dietary zinc, assessed near the time of prostate cancer diagnosis, is associated with an improvement in survival.

This population-based cohort consisted of 525 Swedish men less than 80 years of age with a diagnosis of prostate cancer made between 1989 and 1994. Study participants completed food-frequency questionnaires, and zinc intake was derived from nutrient databases. Deaths from prostate cancer as well as from all causes were documented through February 2009.

After an average follow-up of 6.4 years, 218 (42%) men died of prostate cancer and 257 (49%) died of other causes. Compared to the group with lowest zinc intakes, high dietary zinc intake was associated with a reduced risk of prostate cancer-specific mortality. The association was stronger in men with localized tumors. Zinc intake was not associated with mortality from other causes.

The results of this study suggest that high dietary intake of zinc is associated with lower prostate cancer-specific mortality after diagnosis, particularly in men with localized tumors.

Epstein MM, et al. Dietary zinc and prostate cancer survival in a Swedish cohort. 2011. Am J Clin Nutr 93(3):586-93.

Vegan Diets Short on Omega-3 and Vitamin B12 May Increase Cardiovascular Risk

According to a new review, vegetarian and vegan diets may require additional omega-3 and vitamin B12 supplementation to reduce factors that increase heart disease risk.

A new review in the Journal of Agricultural and Food Chemistry indicates that many vegetarians, especially vegans, may unknowingly be at risk for certain cardiovascular health problems due to inadequate intakes of omega-3 fatty acids and vitamin B12.

The review stated that although meat eaters are known to have a significantly higher combination of cardiovascular risk factors than vegetarians, people following strict vegetarian and vegan diets are not invulnerable to risk. These diets tend to lack several key nutrients, including iron, zinc, vitamin B12, and omega-3 fatty acids.

Meat eaters are known to have a significantly higher incidence of certain cardiovascular risk factors compared with vegetarians, including increased BMI and waist-to-hip ratio, and higher blood pressure, plasma total cholesterol, and triglycerides. However, after reviewing 30 years of studies on vegetarianism, vegetarians and vegans typically have lower concentrations of serum vitamin B12 and omega-3 polyunsaturated fatty acid levels in tissue membrane phospholipids when compared to meat eaters.

Risks associated with low vitamin B12 and omega-3 status include an increase in blood clotting (platelet aggregation) due to increased levels of homocysteine, and decreased levels of ‘good’ HDL-cholesterol. Low HDL cholesterol and high homocysteine levels may be linked to an increase in cardiovascular and stroke risk.

The authors suggest that vegetarians, especially vegans, could benefit from increased dietary intake of omega-3 fatty acids to improve the balance and ratio of omega-3s to omega-6s. They can also benefit from increased vitamin B12 intake, including use of supplements containing vitamin B12 if necessary. Increasing dietary or supplemental omega-3 and vitamin B12 may reduce clotting tendencies that increase vegetarian and vegans’ otherwise low risk of cardiovascular disease.

Duo Li. Chemistry behind Vegetarianism. 2011. J Agric Food Chem 59(3):777–84.

During Pregnancy, Low–Glycemic Diets Improve Health Outcomes in Obese Women & Their Infants

A new study shows that a low-glycemic load diet in overweight and obese pregnant women results in longer pregnancy duration, greater infant head circumference, and improved maternal cardiovascular risk factors.
Read more about this research below.

Excess body weight is known to complicate pregnancies, but the optimal diet during pregnancy is currently unknown. New research published in the American Journal of Clinical Nutrition aimed to examine the effects of a low–glycemic load (low-GL) diet in overweight and obese pregnant women.

Researchers randomly assigned 46 overweight or obese pregnant women to receive a low-GL or a low-fat diet. The women received carbohydrate-rich foods, fats, and snack foods through home delivery or study visits. Birth weight, infant body measurements, gestational duration, maternal weight gain, and maternal metabolic parameters were measured.

No significant differences in birth weight or measures of infant body fat were seen between the two groups. However, in the low-GL compared with the low-fat group, gestational duration was significantly longer and fewer deliveries occurred at less than 38.0 weeks (13% versus 48%). Adjusted head circumference was greater in the low-GL versus the low-fat group. Women in the low-GL group had smaller increases in triglycerides and total cholesterol and a greater decrease in C-reactive protein (a marker of inflammation).
In this study, a low-GL diet correlated with longer pregnancy duration, greater infant head circumference, and improved maternal cardiovascular risk factors. Researchers suggest that large-scale studies may be useful in determining whether a low-GL diet may be beneficial in the prevention of prematurity and other unfavorable maternal and infant outcomes.

Rhodes ET, et al. Effects of a low–glycemic load diet in overweight and obese pregnant women: a pilot randomized controlled trial. 2010. Am J Clin Nutr 92(6):1306-15.