Taking vitamin B or omega-3 PUFAs has been found in previous studies to be inversely related to CVD. The potential mechanisms relating to this are attributed to their roles in lowering risk factors of CVD including plasma homocysteine, circulating triglycerides and the C-reaction protein and implicated in the thickening of the arteries and when the large blood vessels on the heart’s surface narrow instead of dilating.
In spite of this, the review carried out by researchers at Texas State University, found that a recent meta-analysis including 15 randomised controlled trials showed that B vitamin supplements (B6, folate or B12) given alone had very impact on CVD prevention although five other trials had shown folic acid to be beneficial in CVD reduction. Additionally, 79 trials showed little to no effect of increasing omega-3 PUFAs intake, particularly in the form of supplements on CVD prevention.
However, results from several clinical trials revealed a potential synergetic influence of B vitamins and omega-3 PUFAs to prevent CVD.
The authors of the review said: “Although several studies have demonstrated that the combined supplementation of B vitamins and omega-3 PUFAs has diverse effects on the CVD factors, it is insufficient to draw any firm conclusions as to whether B vitamins can further enhance the potential beneficial effects of omega-3 PUFA intake on either primary or secondary prevention of CVD.”
They said that although the combined supplementation of B vitamins and omega-3 PUFAs may have more beneficial impact on CVD prevention than B vitamins or omega-3 PUFAs given separately, dietic strategies for preventing CVD need to focus more on the importance of considering effects at the whole food and dietary patterns level. They wrote that healthy dietary patterns including foods rich in B vitamins or and omega-3 PUFAs such as fish, vegetables, fruit, legumes, nuts and eggs are more likely to be more useful for preventing or treating CVD because they provide other beneficial nutrients which are not present in pure supplements. The focus of primary prevention remains rooted in a whole diet approach.
They said: “For example, the Mediterranean diet which is rich in omega-3 PUFAs and B vitamins, was recently reported to reduce CVD risk from the possible interactions among multiple nutrients in foods abundant in B vitamins and omega-3 PUFAs cannot be ruled out.”
The researchers said that several limitations need to be considered when interpreting the findings from the review. First the supplements were different among the trials ranging from capsules, enriched bake product, emulsified preparation and enriched milk with different doses and combinations of B vitamins and omega-3 PUFAs. The total number of capsules taken in one trial differed which the reviewers say could create bias and owing to the absence of randomisation and/or a placebo-controlled group in some trials, the so-called placebo effect cannot be excluded. There was also no information about the participants’ habitual diet which could be low/high in B vitamins and omega-3 PUFAs which could also bias results.
In conclusion, the author wrote: “The limited evidence from intervention studies indicates that the combined supplementation with B vitamins and omega-3 PUFAs may be promising at reducing plasma homocysteine, triglycerides and low-density lipoprotein cholesterol than each supplement alone. However, there is no solid evidence that the joint supplementation of these two can offer a syngergised effect on preventing CVD and decreasing the relevant morbidity and/or mortality in susceptible populations.”
They added that due to the methodological challenges and heterogeneity in study design of the existing trials, it is difficult to draw any definitive conclusions based on the current literature.
“Therefore, well-designed high-quality trials that will use the combined supplementation of B vitamins and omega-3 PUFAs or dietary patterns rich in these two types of nutrients are warranted,” they said.
Do B Vitamins Enhance the Effect of Omega-3 Polyunsaturated Fatty Acids on Cardiovascular Diseases? A Systematic Review of Clinical Trials
Authors: Jie Zhu et al