AJCN Mar, 2007

[fish oil prevents osteoporosis] Do n–3 fatty acids prevent osteoporosis? “The essential polyunsaturated fatty acids (PUFAs) comprise 2 main classes: n–6 and n–3 fatty acids. The most common source of n–6 fatty acids is linoleic acid (LA), which is found in high concentrations in various vegetable oils. Arachidonic acid (AA), the 20-carbon n–6 fatty acid, is obtained largely by synthesis from LA in the body. The n–3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are found in fish and fish oils. The beneficial health effects of these two n–3 fatty acids were first described in the Greenland Eskimos, who consumed a high-seafood diet and had low rates of coronary heart disease, asthma, type 1 diabetes mellitus, and multiple sclerosis. Since that observation, the positive health attributes of n–3 fatty acids have been extended to include benefits related to cancer, inflammatory bowel disease, rheumatoid arthritis, and psoriasis (1, 2).

Both n–3 and n–6 fatty acids are incorporated into cellular phospholipid membranes, where they serve as precursors to the production of eicosanoids, such as prostaglandins, leukotrienes, and thromboxanes. Eicosanoid metabolites of n–3 fatty acids are less atherogenic, proinflammatory, and vasocontrictive than are the eicosanoids from n–6 fatty acids. ..Therefore, a diet high in n–3 fatty acids favorably modulates the production of eicosanoids and cytokines that play a deleterious role in heart disease, cancer, and autoimmune diseases. The study by Högström et al (4) in this issue of the Journal nicely adds to a growing body of evidence that n–3 fatty acids are also beneficial to bone health. ..found a positive correlation between the n–3 fatty acid content and bone mineral density (BMD). BMD at the spine at age 22 y and changes in spinal BMD between the ages of 16 and 22 y were significantly correlated with higher serum concentrations of total n–3 fatty acids and DHA… A negative association between higher ratios of n–6 to n–3 fatty acids and BMD was also found in an earlier study of elderly men and women (5).”

[urgent need for everyone to take vitamin D]The urgent need to recommend an intake of vitamin D that is effective “during those early years after the discovery of 25(OH)D, the adequacy of its serum concentration was based simply on whether the concentration was enough to prevent osteomalacia or rickets. Three decades later, we know that 25(OH)D concentrations relate to many other aspects of health, including fracture risk, bone density, colon cancer, and even tooth attachment (3); we also know that much higher concentrations of 25(OH)D are needed to prevent adverse outcomes… Randomized trials using the currently recommended intakes of 400 IU vitamin D/d have shown no appreciable reduction in fracture risk (3). In contrast, trials using 700–800 IU vitamin D/d found less fracture incidence, with and without supplemental calcium (3). The reduction in fracture incidence occurs when mean serum 25(OH)D concentrations exceed 72 nmol/L, and this change may result from both improved bone health and reduction in falls due to greater muscle strength (3). ..One recent report associates greater 25(OH)D concentrations with lower risk of nursing home admission; the most desirable category of concentration starts at 75 nmol/L (5).”

[trans-fats and lack of exercise cause diabetes and muscle decay] Skeletal muscle lipid deposition and insulin resistance: effect of dietary fatty acids and exercise ” Mounting evidence indicates that elevated intramyocellular triacylglycerol concentrations are associated with diminished insulin sensitivity in skeletal muscle. This lipid accumulation is most likely due to enhanced fatty acid uptake into the muscle coupled with diminished mitochondrial lipid oxidation. The excess fatty acids are esterified and either stored or metabolized to various molecules that may participate or interfere with normal cellular signaling, particularly insulin-mediated signal transduction, thus altering cellular and, subsequently, whole-body glucose metabolism. Impaired insulin responsiveness, if not managed, can further progress to type 2 diabetes mellitus, an all too common condition. ..Chronic overconsumption of calories coupled with deleterious intakes of saturated or trans-unsaturated fatty acids inconsistent with the recommendations outlined in the Dietary Guidelines for Americans have been shown to increase the risk of insulin resistance. Furthermore, lack of exercise, which can have a profound effect on skeletal muscle lipid turnover, is implicated in this lipid-induced insulin resistance. ”

[Chocolate reduces bad cholesterol and boosts good cholesterol] Continuous intake of polyphenolic compounds containing cocoa powder reduces LDL oxidative susceptibility and has beneficial effects on plasma HDL-cholesterol concentrations in humans “Background: Cocoa powder is rich in polyphenols such as catechins and procyanidins and has been shown in various models to inhibit LDL oxidation and atherogenesis…Conclusion: It is possible that increases in HDL-cholesterol concentrations may contribute to the suppression of LDL oxidation and that polyphenolic substances derived from cocoa powder may contribute to an elevation in HDL cholesterol.”

[To lose weight, avoid sweet and starchy foods-they have high glycemic loads]Effects of a reduced-glycemic-load diet on body weight, body composition, and cardiovascular disease risk markers in overweight and obese adults “Background: Lowering the dietary glycemic load and increasing protein intake may be advantageous for weight management…Conclusion: These findings provide evidence that an ad libitum reduced-glycemic-load diet is a reasonable alternative to a low-fat, portion-controlled eating plan for weight management.”

[Soy improves glycemic control]Soy inclusion in the diet improves features of the metabolic syndrome: a randomized crossover study in postmenopausal women ” Objective:We aimed to determine the effects of soy consumption on components of the metabolic syndrome, plasma lipids, lipoproteins, insulin resistance, and glycemic control in postmenopausal women with the metabolic syndrome. ..Conclusion:Short-term soy-nut consumption improved glycemic control and lipid profiles in postmenopausal women with the metabolic syndrome. ”

[Babies use 470mg calcium/day] Calcium balance in 1–4-y-old children “Conclusions:Bone growth needs in 1–4-y-old children following American diets are met by a daily calcium intake of 470 mg/d, which suggests that the current Adequate Intake of 500 mg/d is close to the actual Estimated Average Requirement. ”

[vitamin D during pregnancy reduces asthma in children] Maternal intake of vitamin D during pregnancy and risk of recurrent wheeze in children at 3 y of age “Background:Vitamin D deficiency and asthma are common at higher latitudes. Although vitamin D has important immunologic effects, its relation with asthma is unknown… Conclusion:In the northeastern United States, a higher maternal intake of vitamin D during pregnancy may decrease the risk of recurrent wheeze in early childhood.”

[Don’t smoke!] Maternal smoking is associated with decreased 5-methyltetrahydrofolate in cord plasma “Conclusions:Cord plasma 5-methyltetrahydrofolic acid (5-MTHFA) concentrations were elevated relative to maternal blood, as expected, because the placenta is capable of concentrative folate transport to the fetus. The negative effect of maternal smoking on infant, but not on maternal, 5-MTHFA status indicates that maternal smoking may impair folate transport to the fetus.”

[probiotics help patients maintain immune system-eat yoghurt] Effects of probiotic therapy in critically ill patients: a randomized, double-blind, placebo-controlled trial “Background: Multiple organ dysfunction syndrome (MODS) is a major cause of mortality in intensive care units. A breakdown in gut barrier function and immune dysfunction are associated with the onset of MODS. Probiotic bacteria have been shown to modulate intestinal barrier and immune function… Conclusion: Patients receiving viable probiotics show a greater enhancement in immune activity than do patients receiving either placebo or probiotic bacterial sonicates. ”

[Healthy elderly benefit from zinc supplements] Zinc supplementation decreases incidence of infections in the elderly: effect of zinc on generation of cytokines and oxidative stress “Objectives: The primary objective was to determine the effect of zinc on the incidence of total infections in healthy elderly subjects. The secondary objective was to determine the effect of zinc on cytokines and oxidative stress markers…both sexes aged 55–87 y…The zinc-supplemented group received zinc gluconate (45 mg elemental Zn/d) orally for 12 mo…Conclusions: After zinc supplementation, the incidence of infections was significantly lower, plasma zinc was significantly higher, and generation of tumor necrosis factor and oxidative stress markers was significantly lower in the zinc-supplemented than in the placebo group.”