Friday, August 31, 2007

Are you getting enough Vitamin D?

Recent studies have proven that higher levels of Vitamin D are vitally required in many health areas, including muscular strength, particularly in the elderly.

2. In 2003 the Mayo Clinic Proceedings online Journal contained an article written by Michael Holic, M.D. entitled “Vitamin D Deficiency: What a Pain It Is”.

He concluded his article with these words: “Prevention of vitamin D deficiency not only preserves bone and muscle health but also may help prevent many chronic diseases and preserve overall health and well-being.”

3. More recently the Journal of Clinical Endocrinology & Metabolism stated that Vitamin D deficiency is common among older people and can cause mineralization defects, bone loss, and muscle weakness. They concluded that “ because almost 50% of the population had serum 25-OHD below 20 ng/ml, public health strategies should be aimed at this group.”

Source: Vitamin D status predicts physical performance and its decline in older persons, Wicherts IS, J Clin Endocrinol Metab. 2007 Jun;92(6):2058-65.

3. Omega 3 fatty acids are also of benefit in maintaining muscle strength, even as we age. Aging cells can develop insulin resistance which has an effect on our ability to build muscle protein.

According to a brief article in FitnessRx for Men: "Omega 3 fatty acids found in fish oil improve insulin resistance, which helps older adults build muscle.”

Source: Long-chain omega-3 fatty acids regulate bovine whole-body protein metabolism by promoting muscle insulin signalling to the Akt–mTOR–S6K1 pathway and insulin sensitivity, AndrĂ©e-Anne Gingras et al, Journal of Physiology 579:269-284, 2007.

4. One recent study in the American Journal of Clinical Nutrition emphasized the urgent need for higher Levels of Vitamin D and that that “Supplemental intake of 400 IU vitamin D/d has only a modest effect on blood concentrations of 25(OH)D, raising them by 7–12 nmol/L, depending on the starting point. To raise 25(OH)D from 50 to 80 nmol/L requires an additional intake of 1,700 IU vitamin D/d”.

They advised that “Correction of low 25(OH)D concentrations can happen only if some or all of the following are implemented:
  • the encouragement of safe moderate exposure of skin to ultraviolet light;
  • appropriate increases in food fortification with vitamin D; and
  • the provision of higher doses of vitamin D in supplements for adults.
Source: The urgent need to recommend an intake of vitamin D that is effective, Vieth R et al, American Journal of Clinical Nutrition, Vol. 85, No. 3, 649-650, March 2007

Omega-3 fatty acid intake associated with lower heart disease risk

Increased consumption of omega-3 fatty acids in the diet is associated with lower levels of inflammation and endothelial activation, according to results from a study at Harvard. Dysfunction of the endothelium, which is the inner lining of the blood vessel wall, is an early event in the development of atherosclerosis and subsequent heart disease. Food frequency questionnaires completed in1986 and 1990 by 727 participants in the Nurses' Health study were evaluated for levels of the omega-3 fatty acids alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). Alpha-linolenic acid consumption was found to be inversely associated with several plasma markers of inflammation, while EPA and DHA intake was inversely related to platelet aggregration. Results of this study indicate that in addition to reducing triglycerides, platelet aggregation and heart arrhythmias, omega-3 fatty acids may also reduce the body's production of hydrogen peroxide, which is involved in the inflammatory process.

Source: Consumption of (n-3) fatty acids is related to plasma biomarkers of inflammation and endothelial activation in women, Lopez-Garcia E, J Nutr 2004 Jul;134(7):1806-11

Tuesday, August 21, 2007

Low Levels of Vitamin D Are Common Among Healthy Children

According to a new study, many kids and adolescents who are otherwise healthy may have inadequate blood levels of vitamin D, a nutrient essential for normal growth and development. A vitamin D deficiency in childhood may lead to muscle weakness, defective bone mineralization and rickets.

A new study published in the July 2007 issue of the American Journal of Clinical Nutrition has found that many children may be at risk for a vitamin D deficiency. Vitamin D is essential for normal growth and development and is important for immune function. The researchers from Children's Hospital of Philadelphia assessed dietary and supplemental vitamin D intake, body mass, and measured blood levels of vitamin D in 382 healthy children between six years and 21 years of age living in the northeastern U.S. and found that more than half of the children had low blood levels of vitamin D. Of the subjects, 55 percent of the children had inadequate vitamin D blood levels and 68 percent overall had low blood levels of the vitamin in the wintertime.

African Americans, children aged 9 and older, and those whose vitamin D intake was low were likeliest to have reduced serum vitamin D levels. "The best indicator of a person's vitamin D status is the blood level of a vitamin D compound called 25-hydroxyvitamin D," Dr. Zemel, the lead investigator noted. "Vitamin D deficiency remains an under-recognized problem overall, and is not well studied in children." The researchers added that further study is needed to determine the appropriate blood levels of vitamin D in children, as well as a review of the current recommendations for vitamin D intake.

Source: Risk factors for low serum 25-hydroxyvitamin D concentrations in otherwise healthy children and adolescents, Francis L Weng, Justine Shults, Mary B Leonard, Virginia A Stallings, and Babette S Zemel, The American Journal of Clinical Nutrition 2007 July; 86(1):150- 8.

Thursday, August 16, 2007

Magnesium intake increases bone mineral density and may reduce the risk of osteoporosis

Image: U.S. Department of Health and Human Services

A study published in the Journal of the American Geriatric Society has shown that dietary intake of magnesium is associated with an increase in bone mineral density in older men and women.

The study included 2,038 men and women aged 70-79 that were enrolled in the Health, Aging and Body Composition Study. Food frequency questionnaires were used to assess magnesium intakes and document any medications. The data also accounted for variations in age, body mass index (BMI), smoking status, alcohol use, physical activity, estrogen use, and supplemental calcium and vitamin D. Higher magnesium intake through diet and supplements was positively associated with total - body bone mineral density (BMD) in older white men and women. For every 100 mg per day increase in magnesium, there was an approximate 2 per cent increase in whole-body BMD.

The results have important implications since osteoporosis currently affects over 10 million adults in the U.S. alone, with another 34 million suspected to have low bone mass. In addition, earlier dietary surveys have consistently shown that a large portion of adults do not meet the RDA for magnesium.

Source: Magnesium Intake from Food and Supplements Is Associated with Bone Mineral Density in Healthy Older White Subjects , Kathryn M. Ryder MD, MS, Ronald I. Shorr MD, MS, Andrew J. Bush PhD, Stephen B. Kritchevsky PhD, Tamara Harris MD, MPH, Katie Stone PhD, Jane Cauley DrPH, Frances A. Tylavsky DrPH (2005), Journal of the American Geriatrics Society November 2005, Vol 53, No 11, pp 1875-1880

Monday, August 06, 2007

High glycemic index diets increase the risk of chronic degenerative disease

Long-term consumption of high-glycemic foods may increase oxidative stress and the risk of chronic degenerative diseases. Leading U.S. researchers recently concluded that a low-GI diet, not a low carbohydrate diet, appears to be beneficial in reducing the production of free radicals and oxidative stress.

Glycemic index (GI) is a measure of the rate that the carbohydrates in a food or meal are digested and appear in the blood as glucose (sugar). Glycemic load is a way of measuring the total carbohydrates in a meal or diet with a mathematical adjustment for GI. These measurements can be used to simultaneously describe the quality (glycemic index) and quantity of carbohydrate in a meal or diet.

Recent data suggest that the sudden rise in blood sugar associated with a high glycemic load may increase free radical production and the risk of oxidative damage. This increased production has been implicated in many disease processes including chronic heart disease, accelerated aging, and type 2 diabetes.

Investigators from several leading U.S. institutions recently investigated whether a diet with a high GI or GL is associated with greater oxidative stress by taking specific measurements in nearly 300 healthy adults. Participants with a higher GI and GL diet were found to exhibit increases in oxidative stress when compared to those eating a diet lower in glycemic index and load.

Researchers concluded that chronic consumption of high-GI foods may lead to chronically high oxidative stress, increasing the risk for several degenerative diseases. A low-GI diet, not a low carbohydrate diet, appears to be beneficial in reducing oxidative stress.

Source: Relations of glycemic index and glycemic load with plasma oxidative stress markers, Youqing Hu, Gladys Block, Edward P Norkus, Jason D Morrow, Marion Dietrich and Mark Hudes, American Journal of Clinical Nutrition, Vol. 84, No. 1, 70-76, July 2006.