Uncategorized Archives - Page 8 of 16

Nearly 6 out of 10 American adults have elevated blood pressure, which is linked to an increased risk of strokes, coronary heart disease, and total mortality. A meta-analysis published in the American Journal of Hypertension analyzed 70 trials to determine the effect of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) on blood pressure.

Weighted differences were used to separate individuals into an EPA+DHA group and a placebo group. All of the studies combined resulted in a 1.52 mm Hg reduction in systolic blood pressure and a 0.99 mm Hg reduction in diastolic blood pressure for the EPA+DHA group over the placebo group. Additional data was used to further separate these into subgroups for additional analysis. This revealed even stronger effects of EPA+DHA, where a 4.51 mm Hg reduction in systolic blood pressure and a 3.05 mm Hg reduction in diastolic blood pressure were observed among untreated hypertensive subjects.

These results continue to build on prior evidence showing that omega-3 fatty acids may play a role in helping individuals control their blood pressure. One of the authors, Dominik Alexander, PhD, noted that “when measuring blood pressure, even small reductions can have a significant clinical impact.” He continues to note that these small differences could be the difference between having to take medication to control blood pressure. A 2 mm Hg reduction in blood pressure reduces stroke mortality by 6%, coronary heart disease mortality by 4%, and total mortality by 3%. In untreated hypertensive individuals, where the EPA and DHA were most effective, EPA+DHA treatment was as effective, or more effective, at lowering blood pressure than increasing physical activity and restricting alcohol and sodium.

Paige E. Miller, Mary Van Elswyk, and Dominik D. Alexander. Long-Chain Omega-3 Fatty Acids Eicosapentaenoic Acid and Docosahexaenoic Acid and Blood Pressure: A Meta-Analysis of Randomized Controlled Trials. Am J Hypertens. 2014 Jul; 27(7): 885–896.

Low intakes of the B vitamins are thought to contribute to depression in some people, but until now there has been little supporting evidence from population-based studies of older adults. In a study published online in the American Journal of Clinical Nutrition, researchers examined whether certain dietary intakes of vitamin B6, vitamin B12, and folic acid correlated with symptoms of depression.

The study group consisted of 3,503 adults aged 65 and older who were followed over an average of 7.2 years. Vitamin intakes from diet and supplements were assessed using food frequency questionnaires, and the presence of depression was measured periodically using a standardized version of the Center for Epidemiologic Studies Depression scale.

After ≤12 years of follow-up, higher B vitamin intakes (including supplementation) were associated with a lower risk of depressive symptoms. The lowered risk remained after adjusting for age, sex, race, education, income, and anti-depressant medication use. The risk of developing depression symptoms decreased by 2 percent for every 10mg (milligram) increase in daily vitamin B6 intake. The same effect was true for every 10µg (microgram) increase in vitamin B12 intake. Increased intakes of the B vitamins through food intake alone did not significantly reduce depression incidence.

Both vitamin B6 and vitamin B12 are involved in healthy nervous system function, but because older adults often have difficulty absorbing the B12 found naturally in food, fortified foods and a multivitamin may be necessary to reach beneficial levels.

The results of this research indicate that high total intakes of vitamins B6 and B12 may be protective against depressive symptoms in older adults.

Skarupski KA, et al. Longitudinal association of vitamin B6, folate, and vitamin B12 with depressive symptoms among older adults over time. AJCN ePub ahead of print, doi:10.3945/ajcn.2010.29413. Retrieved online June 2, 2010.

Previous research has suggested that the B vitamin folate may influence blood pressure (BP) by reducing plasma homocysteine levels and/or increasing nitric oxide synthesis in endothelial cells in the vessels. Research in humans, and in particular longitudinal studies, has been limited. In a paper published in the American Journal of Clinical Nutrition, scientists investigated whether dietary folate intake is associated with the incidence or development of hypertension over a 20 year follow-up period.

This prospective study included 4,400 normotensive men and women aged 18–30 years from the Coronary Artery Risk Development in Young Adults that began in 1985. The young adults were evaluated 6 separate times thereafter, in 1987, 1990, 1992, 1995, 2000, and 2005. Diet was assessed using a dietary-history questionnaire at baseline and in 1992 and 2005. The incidence of hypertension was defined as the first occurrence at any follow-up examination of systolic BP ≥140 mm Hg, diastolic BP ≥90 mm Hg, or use of blood pressure medication.

A total of 989 cases of hypertension were identified during the 20 years of follow-up. Participants in the highest quintile (top 20%) of total folate intake had a 52% lower incidence of hypertension than did those in the lowest quintile. The protective effect of folate was more pronounced in whites than African Americans, although it was significant in both groups.

The results of this study show that higher folate intake in young adulthood was associated with a lower incidence of high blood pressure later in life. More research is needed to establish the specific mechanism or cause of the beneficial association.

Pengcheng Xun et al. Folate intake and incidence of hypertension among American young adults: a 20-y follow-up study. Am J Clin Nutr May 2012 vol. 95 no. 5 1023-1030.

Short periods of intense exercise are known to suppress hunger through appetite regulating hormones. A study published in the American Journal of Clinical Nutrition compared the effects of high-intensity exercise on central (brain) response to visual food stimuli.

The researchers recruited 15 healthy lean men in their early twenties. The study participants completed two 60 minute tests: exercise (running at 70% maximum aerobic capacity) and a resting control. After each test, images of high- and low- calorie foods were viewed and the brain response to the foods was measured using an MRI.

After the exercise session, thirst and core body temperature were increased while appetite response was significantly suppressed. Exercise significantly suppressed ghrelin (an appetite stimulating hormone) and enhanced the release of peptide YY (an appetite reducing hormone). When compared to the resting control, neural (brain) response in the brain’s reward related regions were stimulated in response to viewing the images of low-calorie foods, but suppressed upon viewing images of high-calorie foods.

This study found that high intensity exercise increases neural responses in reward-related regions of the brain in response to images of low-calorie foods, and suppresses activation during the viewing of high-calorie foods. These central responses are associated with exercise-induced changes in peripheral signals related to hydration and appetite-regulation.

Exercise is a well-known important component of a healthy lifestyle. This study provides further evidence that exercise can do more than just providing a caloric deficit, it may also influence you to make healthier food choices.

Crabtree DR, et al. The effects of high-intensity exercise on neural responses to images of food. Am J Clin Nutr. 2014 Feb;99(2):258-67.

The results of a clinical trial published in Arthritis Research and Therapy suggest that supplementing with glucosamine and taking regular walks can improve pain, physical function, and overall activity levels in adults with mild to moderate knee or hip osteoarthritis.

Thirty-six low-activity participants (aged 42 to 73 years) were provided with 1500 mg glucosamine sulfate per day for 6 weeks. At the end of six weeks, the participants began a 12-week progressive walking program (while continuing to take glucosamine.)

Study subjects were given a pedometer to monitor step counts. They were then randomized into two groups – one to walk 3 days per week, the other to walk 5 days per week. The length of the walk was gradually increased over the course of the program, with 6000 per day being the goal by the end of the 12-week period. Physical activity levels, physical function, and arthritis symptoms were analyzed at the beginning and at 6, 12, 18 and 24 weeks.

Physical activity levels, physical function, and pain assessment scores improved during the first 6 weeks of the study (glucosamine supplementation only.) Between the start of the walking program (week 6) and the final follow-up (week 24), further improvements were seen, though most improvements happened between weeks 6 and 12. No significant differences were observed between participants who participated in the 3 and 5 day per week programs.

In people with mild to moderate hip or knee osteoarthritis, walking a minimum of 3,000 steps (approximately 30 minutes) at least 3 days per week, in combination with glucosamine sulfate, may reduce some symptoms of osteoarthritis.

Ng N, et al. Efficacy of a progressive walking program and glucosamine sulphate supplementation on osteoarthritic symptoms of the hip and knee: a feasibility trial. 2010. Arthritis Research & Therapy 12(1):R25.