High seafood intake reduces 10-year risk of CVD-related mortality

27th April 2023

A high seafood intake and in particular small fish rich in omega-3 fatty acids reduces the 10-year risk of cardiovascular disease mortality

The benefits of seafood (SF) intake such as fish exceed the potential risks from contaminants. In fact, an umbrella review identified the beneficial effect of fish intake for a range of chronic diseases. However, another review suggests only a small effect on cardiovascular mortality from eating fish. In addition, other and more recent work, proposes that the health benefits are only due to fatty fish, e.g., sardines, salmon etc.

In the current study, researchers wanted to tease out the benefits of a higher SF intake. They considered total servings of seafood and small fatty fish rich in omega-3 fatty acids separately. Using a self-reported questionnaire, SF intake was categorised as high (>2 servings/week) or low (≤2 servings/week) intake). Similarly, intake of small fatty acid fish was also high or low (> 1 serving or < 1 serving/week). The incidence of both non-fatal and/or fatal CVD events served as the outcomes of interest after 10- and 20-years.

Seafood intake and cardiovascular events

There were 2,020 individuals with a mean age of 45.2 years (50.2% female) with data for analysis. Furthermore, only 32.7% and 9.6% of the entire cohort had a high SF and small fish intake respectively.

Those consuming a high seafood intake, had a 27% lower risk of developing CVD over the next 10 years. However, this risk became non-significant in fully-adjusted models (hazard ratio, HR = 0.76, 95% CI 0.65 – 1.02). In contrast, the 10-year CVD-related mortality was significantly lower in those with a high SF intake (HR = 0.26, 95% CI 0.11 – 0.58). This was also true for a high intake of fatty fish (HR = 0.24, 95% CI 0.06 – 0.99). In addition, the 20-year CVD-related deaths were also lower for a high SF intake (HR = 0.76, 95% CI 0.55 – 0.98).

Therefore a high intake of seafood and particularly fish rich in omega-3 fatty acids, was associated with a lower risk of 10-year fatal and non-fatal CVD. 

Citation
Critselis E et al. High fish intake rich in n-3 polyunsaturated fatty acids reduces cardiovascular disease incidence in healthy adults: The ATTICA cohort study (2002-2022) Front Physiol 2023

Combination of exercise, omega-3 fatty acids and vitamin D reduces cancer risk in the elderly

13th May 2022

A randomised trial has found that a combination of exercise, omega-3 fatty acids and vitamin D significantly reduces cancer risk in patients over 70

Cancer is the second leading cause of death globally and in 2018, it accounted for approximately 9.6 million deaths. Although cancer can strike at any age, many types of cancer become more prevalent with increasing age.

However, recent research has found that for most adults, cancer does not have to be an inevitable consequence of growing older. In fact, adoption of healthy lifestyle measures based on a combination of exercise, diet, smoking status, alcohol consumption, and anthropometry, in other words, simple behavioural modifications, have been shown to produce a sizeable reduction in the risk of some cancers.

Among healthy interventions, there is evidence that physical activity is associated with a lower risk of several cancers. Equally, use of vitamin D supplements has some evidence to support its use in reducing the incidence of advanced (metastatic or fatal) cancer.

Finally, an omega-3 fatty acid-rich diet, can significantly delay mouse tumour growth when compared with a monounsaturated fatty acid-rich diet. Nevertheless, whether a combination of exercise, vitamin D and omega-3 fatty acids provides a synergistic and preventative effect against cancer is less clear.

For the present study, the researchers undertook a randomised controlled trial, which sought to examine the combination of exercise, supplementation with vitamin D and omega-3 fatty acids in older adults and how this impacted on the subsequent development of cancer.

Their DO-HEALTH trial examined the combined effect of simple home strength exercise (SHEP), vitamin D (2000 IU/day) and/or 1g/day of marine omega-3 fatty acids, in healthy adults 70 years of age and older. For the primary outcome, the team considered the time to the development of a verified invasive cancer.

Combination of exercise, omega-3 fatty acids, vitamin D and cancer development

A total of 2157 individuals with a mean age of 74.9 years (61.7% female) were included in the study and followed for a median of 2.99 years. During this period of time there were 81 invasive cancers diagnosed and verified.

For the three separate interventions, the adjusted hazard ratios (compared to controls) were 0.76 (95% CI 0.49 – 1.18) for vitamin D, 0.70 (95% CI 0.44 – 1.09) for omega-3 fatty acids and 0.74 (95% CI 0.48 – 1.15) for SHEP). In other words, while there were beneficial effects from the individual interventions, the effects were not statistically significant, but when two of the interventions were combined, the effect did become statistically significant.

For instance, the combination of SHEP and omega-3 resulted in an adjusted hazard ratio of 0.52 (95% CI 0.28 – 0.97, p = 0.039). However, the greatest benefit was derived from the combination of exercise, vitamin D and omega-3 fatty acids, with an adjusted hazard ratio of 0.39 (95% CI 0.18 – 0.85, p = 0.017).

The authors calculated that the number needed to treat to prevent one incident case of cancer after three years with the three treatments combined was 35.

They concluded that future studies should focus on the benefit of combining interventions as a means of cancer prevention.

Citation
Bischoff-Ferrari HA et al. Combined Vitamin D, Omega-3 Fatty Acids, and a Simple Home Exercise Program May Reduce Cancer Risk Among Active Adults Aged 70 and Older: A Randomized Clinical Trial Am J Clin Nutr 2022

Vitamin D and omega-3 fatty acids reduce autoimmune disease incidence

2nd February 2022

Vitamin D and omega-3 fatty acids when taken for a period of 5 years have been found to reduce the incidence of new autoimmune disease

Vitamin D and omega-3 fatty acids taken by adults over a 5-year period led to a 22% reduction in the incidence of autoimmune disease compared to placebo. This was the conclusion of a randomised trial by researchers from the Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, USA.

An autoimmune disease develops due to an immune-mediated attack on the body’s own organs although the underlying pathology for most conditions remains uncertain. Moreover, an estimated 4% of the global population is affected by one of the 80 different autoimmune disease which include conditions such as type 1 diabetes, rheumatoid arthritis, lupus, Crohn’s disease and scleroderma. Although epidemiological evidence indicates a potential preventative role for vitamin D in autoimmune diseases, prospective data are lacking. In addition, a Danish cohort study found that each additional 30g intake of fatty fish containing omega-3 oils was associated with 49% reduction in the risk of rheumatoid arthritis.

However, little is known about the potential synergistic effect of vitamin D and omega-3 fatty acids on the development of an autoimmune disease and this was the purpose of the present study by the US team. They undertook a randomised, placebo-controlled trial, VITAL, which was designed to investigate whether taking daily supplements of vitamin D3 (2000 IU) or omega-3 fatty acids reduced the risk of developing cancer, heart disease, and stroke in people who do not have a prior history of these illnesses. However, for the present analysis, the team focused on the development of the autoimmune diseases such as rheumatoid arthritis, polymyalgia rheumatica, autoimmune thyroid disease and psoriasis. For the trial, participants were randomised to vitamin D or matching placebo and omega-3 fatty acids or matched placebo and self-reported all incidence autoimmune diseases which were confirmed by a review of their medical records. The primary outcome of interest was the incidence of all autoimmune diseases.

Vitamin D and omega-3 fatty acids and autoimmune diseases

A total of 25,871 individuals with a mean age of 67.1 years (50.6% female) were enrolled and followed for a median of 5.3 years. In the vitamin D arm, 123 individuals and 155 in the placebo group had a confirmed autoimmune disease (hazard ratio, HR = 0.78, 95% CI 0.61 – 0.99, p = 0.05). In the separate omega-3 fatty acids arm, 130 compared with 148 in the placebo group developed an autoimmune disease although this difference was non-significant (HR = 0.85, 95% CI 0.67 – 1.08, p = 0.19).

Using a Cox model adjusted for age, sex and race, the authors found that among those randomised to both vitamin D and omega-3, the incidence of confirmed autoimmune disease was lower (HR = 0.69, 95% CI 0.49 – 0.96) compared with placebo.

They concluded that vitamin D supplements with or without omega-3 fatty acids reduced the development of autoimmune diseases.

Citation

Hahn J et al. Vitamin D and marine omega 3 fatty acid supplementation and incident autoimmune disease: VITAL randomized controlled trial BMJ 2022