In the news: Omega-3s Slow Muscle Loss with Disuse Good Vitamin D Levels? Think Magnesium

Omega-3 Fatty Acids May Help Muscles

The saying ‘use it or lose it’ is often used to describe what happens to muscles when they’re inactive. Muscles tend to shrink or ‘atrophy’ from lack of physical activity when injury or disease makes it difficult or impossible to move an arm or a leg.

Because omega-3 fatty acids play a role in muscle protein production, researchers at McMaster University's Department of Kinesiology in Canada decided to study whether fish oil supplementation could slow the loss of muscle mass during periods of muscle disuse due to immobilization (1).

This small but novel study involved 20 healthy young women who received either high dose fish oil or a placebo for 4 weeks.

At the end of that 4-week period, the participants each wore a knee brace that immobilized one leg for 2 weeks. The women then entered a recovery phase for another 2 weeks, during which they went back to their normal everyday activities.

The researchers measured leg muscle size, mass, strength and protein synthesis before and after the immobilization, as well as after the recovery period. The results showed that the fish oil group lost significantly less muscle volume (size) compared to the placebo group. Muscle volume also returned to pre-immobilization levels after the recovery period for the fish oil group, while it remained lower in the placebo takers. Muscle mass (the amount of muscle) was reduced only in the placebo group.

Analysis of muscle tissue samples taken from the participants revealed that muscle protein production was higher in the omega-3 group than in the placebo group throughout the study.

According to the lead author, the findings suggest that young women may be able to use supplemental omega-3 to slow muscle loss and enhance recovery in situations where one of their limbs is immobilized.

Magnesium Crucial for Vitamin D Metabolism

A recent trial (2) by Vanderbilt-Ingram Cancer Center researchers found that a more optimal intake of magnesium can optimize vitamin D status, raising it in people with deficient levels, and lowering it in people with high levels.

The Vanderbilt findings could help explain the inconsistent results seen in population health and clinical studies that have looked at vitamin D and the risk of colorectal cancer and heart disease.

Because magnesium is required to fully activate vitamin D, having inadequate levels of this mineral can mean that much of vitamin D in the body remains stored and inactive. This is important because national surveys indicate that 79% of American adults don’t meet the RDA for magnesium.

The study included 180 participants at high risk of colorectal cancer, who received either a placebo or supplemental magnesium in amounts that were customized for each person based on their baseline levels of dietary intake.

The amounts of magnesium were tailored to bring the participant’s calcium to magnesium intake ratio to about 2.3. The average amount supplemented was a little over 200 mg of magnesium daily.

These study results are in agreement with those of an earlier study (3) by the same researchers that linked higher magnesium (from diet, supplements or both) with a lower risk of vitamin D inadequacy /deficiency.

The take home message? If you’re trying to improve your vitamin D levels, don’t forget magnesium. Good sources include dark leafy greens, beans, whole grains, fatty fish and nuts.

References

1. McGlory C, et al. Omega-3 fatty acid supplementation attenuates skeletal muscle disuse atrophy during two weeks of unilateral leg immobilization in healthy young women. FASEB. Epub ahead of print Jan, 2019.
2. Qi Dai, et al. Magnesium status and supplementation influence vitamin D status and metabolism: results from a randomized trial. Am J Clin Nutr. 108:1249–58, 2018.
3. Deng X, et al. Magnesium, vitamin D status and mortality: results from US National Health and Nutrition Examination Survey (NHANES) 2001 to 2006 and NHANES III. BMC Med. 11:187, 2013.