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Dietary supplements

Dietary magnesium linked to reduced risk of heart disease, stroke & diabetes

A meta-analysis of 40 epidemiological studies from 1999 to 2016 has concluded that that people in the highest category of dietary magnesium consumption had a 10% lower risk of coronary heart disease, 12% lower risk of stroke and a 26% lower risk of type-2 diabetes compared to those in the lowest category. A dose–response analysis revealed that a 100 mg/day increase in dietary magnesium intake is significantly associated with a 7%, 22%, and 19% decrease in the risk of stroke, heart failure, and type 2 diabetes, respectively.

Magnesium-rich foods include spices, nuts, beans, cocoa, whole grains and green leafy vegetables.

Magnesium deficiency is relatively common, estimated to affect between 2.5% and 15% of the population. The recommended dietary allowance of magnesium is 350mg/day for an average male adult and 300mg/day for an average adult female, with an additional 150mg/day during pregnancy and lactation

https://www.biomedcentral.com/about/press-centre/science-press-releases/08-12-16

https://www.eurekalert.org/pub_releases/2016-12/bc-dma120516.php

Fudi Wang et al. 2016. Dietary magnesium intake and risk of cardiovascular disease, type 2 diabetes, and allcause mortality: A dose-response meta-analysis of prospective cohort studies. BMC Medicine, DOI: 10.1186/s12916-016-0742-z

Folate intake can be too high for some

Another warning about supplements comes from a finding that older adults taking more than twice the recommended daily allowance (RDA) of folate were more likely to have peripheral neuropathy if they had a common genetic variant linked to reduced cellular vitamin B12 availability.

B12 deficiency is a common problem for older adults, and those with this gene variant (estimated to occur in one in six Americans) are vulnerable to conditions related to vitamin B12 deficiency even if they consume normal amounts of B12.

The study, involving 171 older adults (60+), found that those with the GG variant of the TCN2 gene were three times more likely to develop peripheral neuropathy. But among those who consumed more than twice the RDA of 800 micrograms of folate, individuals with the gene variant had seven times the risk of peripheral neuropathy compared to those without. There was no significant difference for those consuming less than 800 micrograms of folate a day.

Note that the average daily folate intake for U.S. adults over 50 is in fact more than twice the Recommended Daily Allowance. Moreover, it's estimated that some 35% of Americans take folate supplements.

https://www.eurekalert.org/pub_releases/2016-10/tuhs-hfi100716.php

Hathairat Sawaengsri, Peter R Bergethon, Wei Qiao Qiu, Tammy M Scott, Paul F Jacques, Jacob Selhub, and Ligi Paul Transcobalamin 776C→G polymorphism is associated with peripheral neuropathy in elderly individuals with high folate intake Am J Clin Nutr 2016 104: 6 1665-1670; First published online October 12, 2016. doi:10.3945/ajcn.116.139030 

No benefit in omega-3 supplements for cognitive decline

A large, five-year study challenges the idea that omega-3 fatty acids can slow age-related cognitive decline. The study, involving 4,000 older adults, was part of the Age-Related Eye Disease Study (AREDS), which established that daily high doses of certain antioxidants and minerals can help slow the progression of age-related macular degeneration. However, a follow-up study found the addition of omega-3 fatty acids to the AREDS formula made no difference.

Link between fatty acids and heart disease complex

Submitted by Fiona McPherson on

A meta-analysis of 72 studies with over 600,000 participants from 18 nations has concluded that total saturated fatty acid, whether measured in the diet or in the bloodstream as a biomarker, was not associated with coronary disease risk. Nor was there any significant association between consumption of total monounsaturated fatty acids, long-chain omega-3 and omega-6 polyunsaturated fatty acids, and cardiovascular risk.

Dietary guidelines for choline may be insufficient

Submitted by Fiona McPherson on

A study involving healthy men and women fed a baseline diet containing 550 mg choline/day (the adequate intake level set by the Institute of Medicine) for 10 days, then put on a low choline diet (50 mg choline/day) for up to 42 days, has found that the "right" amount of choline depends on many factors, including gender, age, and ethnicity.

http://www.eurekalert.org/pub_releases/2014-03/foas-osd032714.php

Pycnogenol improves cognition in college students in small trial

Back in 2008, I reported on a small study that found that daily doses of Pycnogenol® for three months improved working memory in older adults, and noted research indicating that the extract from the bark of the French maritime pine tree had reduced symptoms in children with ADHD. Now another study, involving 53 Italian university students, has found that cognitive performance improved in those taking 100 mg of Pycnogenol every day for eight weeks.

Dietary supplements

Older news items (pre-2010) brought over from the old website

Evidence mounts against DHEA use in treating cognitive decline

DHEA is a naturally-occurring hormone in the human body that declines with age. Previous research looking at the effect of DHEA supplementation on cognitive function and quality-of-life has produced inconsistent results. In the first long-term study (12 months) of healthy older adults, 110 men and 115 women aged 55-85 received either daily 50 mg doses of DHEA or a similar looking placebo pill for 1 year. It was found that, although youthful levels of DHEA were restored in the treatment group, the supplements had no benefits for cognitive function or quality-of-life in this representative sample.

Kritz-Silverstein, D., von Mühlen, D., Laughlin, G. A., & Bettencourt, R. (2008). Effects of Dehydroepiandrosterone Supplementation on Cognitive Function and Quality of Life: The DHEA and Well-Ness (DAWN) Trial. Journal of the American Geriatrics Society, 56(7), 1292-1298. Retrieved from http://dx.doi.org/10.1111/j.1532-5415.2008.01768.x

http://www.eurekalert.org/pub_releases/2008-05/w-ema052108.php

French maritime pine bark improves memory in elderly

A double-blind, placebo controlled, matched pairs study examined the effects of Pycnogenol (an antioxidant plant extract from the bark of the French maritime pine tree) on a range of cognitive and biochemical measures in 101 senior individuals aged 60-85 years old. Participants had a daily dose of 150mg for three months. Pycnogenol improved both numerical working memory as well as spatial working memory. Blood samples revealed that F2-isoprostanes significantly decreased with Pycnogenol, a sign of reduced oxidation of nerve membranes, suggesting that the antioxidant activity of Pycnogenol plays a major role for the clinical effects. Several recent research studies have found Pycnogenol reduced ADHD symptoms such as hyperactivity and improved attention, concentration and motor-visual coordination in children with ADHD. Pycnogenol extract has been studied for 35 years and is available in more than 600 dietary supplements.

Ryan, J., Croft, K., Mori, T., Wesnes, K., Spong, J., Downey, L., … Stough, C. (2008). An examination of the effects of the antioxidant Pycnogenol(R) on cognitive performance, serum lipid profile, endocrinological and oxidative stress biomarkers in an elderly population. J Psychopharmacol, 22(5), 553-562. Retrieved from http://jop.sagepub.com/cgi/content/abstract/22/5/553

http://www.eurekalert.org/pub_releases/2008-03/mg-nsp031708.php

Long-term beta carotene supplementation may help prevent cognitive decline

A large, long-running study has found that men who took beta carotene supplements for 15 years or longer had significantly higher scores on several cognitive tests compared with men who took placebo. There was no such effect in those men who took the supplements for a year. The researchers suggest that although the benefits were modest in themselves, they may predict substantial differences in eventual risk of dementia. However, it should be noted that beta carotene is not without risks—for example, it may increase the risk of lung cancer in smokers — and that it would be premature to advise use of such supplements.

Grodstein, F., Kang, J. H., Glynn, R. J., Cook, N. R., & Gaziano, M. (2007). A Randomized Trial of Beta Carotene Supplementation and Cognitive Function in Men: The Physicians’ Health Study II. Arch Intern Med, 167(20), 2184-2190. Retrieved from http://archinte.ama-assn.org/cgi/content/abstract/167/20/2184

http://www.eurekalert.org/pub_releases/2007-11/jaaj-lbc110807.php

Dietary supplements improve old rats' memory and energy levels

After only a month, older rats fed two chemicals normally found in the body's cells and available as dietary supplements — acetyl-L-carnitine and an antioxidant, alpha-lipoic acid — performed better on memory tests, and had noticeably more energy (on a par with a “middle-aged” rat). It is thought that these chemicals act on the mitochondria, the “power-houses” of the cells. Mitochondria are increasingly being implicated as especially vulnerable to the aging process. Carnitine is a natural compound produced in the cell and obtained in the diet through meats and vegetables. It has been shown to improve balance and short-term memory in human. Lipoic acid is found in green, leafy vegetables.
The University of California has patented use of the combination of the two supplements to rejuvenate cells. Human clinical trials are currently underway.

Hagen, T. M., Liu, J., Lykkesfeldt, J., Wehr, C. M., Ingersoll, R. T., Vinarsky, V., … Ames, B. N. (2002). Feeding acetyl-l-carnitine and lipoic acid to old rats significantly improves metabolic function while decreasing oxidative stress. Proceedings of the National Academy of Sciences of the United States of America, 99(4), 1870-1875. Retrieved from http://www.pnas.org/content/99/4/1870.abstract

Liu, J., Head, E., Gharib, A. M., Yuan, W., Ingersoll, R. T., Hagen, T. M., … Ames, B. N. (2002). Memory loss in old rats is associated with brain mitochondrial decay and RNA/DNA oxidation: Partial reversal by feeding acetyl-l-carnitine and/or R-α-lipoic acid. Proceedings of the National Academy of Sciences of the United States of America, 99(4), 2356-2361. Retrieved from http://www.pnas.org/content/99/4/2356.abstract

Liu, J., Killilea, D. W., & Ames, B. N. (2002). Age-associated mitochondrial oxidative decay: Improvement of carnitine acetyltransferase substrate-binding affinity and activity in brain by feeding old rats acetyl-l- carnitine and/or R-α-lipoic acid. Proceedings of the National Academy of Sciences of the United States of America, 99(4), 1876-1881. Retrieved from http://www.pnas.org/content/99/4/1876.abstract

http://www.eurekalert.org/pub_releases/2002-02/uoc--dsm021502.php
http://www.eurekalert.org/pub_releases/2002-02/osu-crr021902.htm

DHA improves memory in older adults with cognitive impairment

There have been mixed findings about the benefits of DHA (an omega-3 fatty acid), but in a study involving 485 older adults (55+) with age-related cognitive impairment, those randomly assigned to take DHA for six months improved the score on a visuospatial learning and episodic memory test. Higher levels of DHA in the blood correlated with better scores on the paired associate learning task. DHA supplementation was also associated with better verbal recognition, but not better working memory or executive function.

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