In the news: Vitamin D & Omega-3 in Autoimmune Disease; Choosing Healthy Salmon

VITAL Trial Follow-up Suggests Long Term Vitamin D May Lower Autoimmune Disease Risk

The VITamin D and OmegA-3 TriaL (VITAL) study was a large scale trial designed primarily to evaluate the effects of vitamin D and omega-3 supplementation on the development of cancer and cardiovascular disease.

The VITAL study also looked at the potential effects of these nutrients on autoimmune diseases.

After 5 years, the VITAL researchers reported that vitamin D supplementation (2,000 IU daily) was associated with a 22% risk reduction for confirmed autoimmune diseases. Supplementing with omega-3 fatty acids (460 mg EPA and 380 mg DHA) was also linked to an 18% lower risk of autoimmune conditions.

The investigators wanted to know whether these effects last over time. So after discontinuing daily supplementation at the end of the 5-year VITAL study, 21,000 plus participations agreed to be followed for an additional 2 years.

The recently published findings(1) show that the benefit from vitamin D in helping to protect against autoimmune diseases waned after two years while the protection seen with omega-3s appeared to last during the follow-up period.

The results, according to the authors, suggest that vitamin D may have to be supplemented on a continuous basis in order to lower the likelihood of developing an autoimmune disease. The benefits of omega-3s, on the other hand, may last for at least two years after discontinuing supplementation.

The lead researcher indicated that the beneficial effect of vitamin D seemed strongest for psoriasis, while the effects of omega-3 appeared strongest for rheumatoid arthritis and inflammatory bowel disease.

However, further research is needed to better clarify which autoimmune conditions may be affected by either or both supplements, and which patients may benefit.

Sorting Through Fresh Salmon Choices

We all know that salmon is not only one of the healthiest fish, but one of the healthiest food choices as well. However, the lack of food labeling for fresh fish may be a source of confusion when it comes to choosing what kind to buy. Wild or farmed? Chinook or Sockeye? And what about mercury contamination?

Canadian university researchers undertook analysis of six types of salmon to compare their nutrient and mercury content. The species analyzed included farmed Atlantic, farmed organic Atlantic, farmed organic Chinook, wild Chinook, wild Pacific (pink), and wild Sockeye(2).

Wild Chinook and wild Sockeye were found to be the most nutrient dense and have the highest omega-3 fatty acid content (EPA and DHA).

However, the authors point out that it’s really the species of salmon that makes the biggest difference in nutritional quality – not whether it was farm raised or wild caught, or whether it's certified organic or environmentally certified. For example, there was a big difference in the wild salmon they looked at – between Sockeye, Chinook and Pacific.

When it came to mercury contamination, farmed Atlantic salmon had the lowest mercury content as well as high nutrient density, though all the species tested had levels far below international safety levels. All types were safe and nutritious. According to the authors, “Sockeye and Chinook can be consumed less frequently for the same nutritional value. However, they are expensive and there are limits on sustainable catch levels. But if you enjoy eating salmon more frequently, farmed Atlantic is a great option for its nutritional value, cost, availability and low mercury”(3).

References

1. Costenbader K, et al. Vitamin D and marine n-3 fatty acids for autoimmune disease prevention: Outcomes two years after completion of a double-blind, placebo-controlled trial. Arthritis Rheumatol. Jan 25, 2024.
2. Colombo SM and Mazal X . Investigation of the nutritional composition of different types of salmon available to Canadian consumers. J Ag Food Res. 2, 2020.
3. Dalhousie University https://www.dal.ca/news/2020/07/09/new-research-reveals-surprising-differences-between-salmon-speci.html