According to new research, supplementing with key B-vitamins provide general immune protection and protection against Covid-19 specifically.

The research was conducted by examining the B-vitamin intake of 9,189 adults then comparing that intake with the likelihood of contracting Covid-19, as well as the duration and severity.

The study was a collaboration of scientists from four universities in Iran and was published in The British Journal of Nutrition in November 2022.

According to the findings, supplementation with Vitamin B5 reduced the odds of developing Covid-19 by 47%, while moderate intake of Vitamin B12 offered a measurable level of viral protection.

The researchers noted the study was built on two already-established facts: One, Covid-19 severity is dependent on how robust an individual’s immune system is; and two, B-vitamins are a critical part of maintaining an healthy immune function.

“Nutrition and dietary components as modifiable factors can play a bilateral role in strengthening or weakening the immune system,” the researchers wrote.

“B-vitamins are not synthesized in the human body. So, they must be consumed regularly in the diet. Many body functions, including energy production, methylation, synthesis, DNA repair, and enzyme functions, depend on B-vitamins’ functions.”

Study details

To conduct the study, researchers utilized dietary data from two previous Iranian data collections: The Yazd Health Study and the Taghzieh Mardom-e-Yazd Study. The 9,189 participants were aged between 20 and 69 years old.

Covid-19 incidence was determined through PCR tests, while serological assays were used to estimate immunoglobulin M and immunoglobulin G antibodies in symptomatic or asymptomatic Covid subjects.

Dietary intake was assessed with a food frequency questionnaire covering one year and included all food groups. A questionnaire was also used to assess level of daily physical activity.

Subjects were divided into four quartiles based on B-vitamin intake, with the first comprising those with the lowest intake and used as a reference. Subjects in the second quartile reported low intake, the third moderate intake, and the fourth high intake.

Findings included:

Dietary intake of Vitamin B5 demonstrated the highest protective association with Covid-19 and corresponded to a 47% reduction in odds.

Commenting on this finding, the researchers wrote:

“The protective effect of Vitamin B5 may partially be explained by its involvement in immune response as well as its anti-inflammatory properties. Vitamin B5 boosts macrophage maturation, increases macrophage phagocytosis, and promotes Th1 and Th17 cell differentiation.”


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Even moderate Vitamin B12 intake also reduced the odds of contracting Covid-19, compared to the lowest quartile.

There were notable differences in participants’ gender: The researchers note high intake of Vitamin B6 in women and moderate intake by men lowered the odds of infection compared to the lowest quartile. High intake of Vitamin B5 and Vitamin B7 also reduced the odds for men.

There were notable differences in participants with unhealthy body weight: The researchers reported that subjects with a BMI less than 25 who consumed high B7 and B12 displayed lower Covid-19 odds; however, for those with a BMI above 25, it was high B6 that appeared to be the effective protector.

In what could be seen as a nod to the benefit of taking a multiple B-vitamin supplement just to “cover all the bases,” the researchers found that different B-vitamins affected healthy and unhealthy individuals differently.

For example, tests revealed lower virus odds with high Vitamin B9 and B-complex when subjects presented with at least one chronic disease (when compared to the lowest quartile). Meanwhile, in test subjects with no chronic disease, moderate consumption of B7 and B12 reduced the odds on contracting Covid.

Concluding thoughts

“B vitamins are essential micro-nutrients for the body with antioxidant, anti-inflammatory, and immune-regulating properties,” the researchers wrote.

“Results from this study could expand previous findings on nutrition implication in Covid-19 risk and highlight the potential protective effects of dietary intake of B-vitamins.”

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Fortify your immune system with B-vitamins found in the following Optimal Health Systems products:

Exposure Protection Pak
Optimal Female+B
Optimal Health Kit
Optimal Whole Food Vitamin-Mineral

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Source: British Journal of Nutrition/Cambridge.org, Wikipedia (for definitions).