PUFA protection: women’s heightened requirements through life stages

This was the conclusion of a presentation by Professor Wendy Hall from the Kings College London, during the Nutrition Society Summer Conference, earlier this month.

She emphasised the prevalence of EPA and DHA deficiencies within women as a result of hormonal and tissue demand changes adding that conditions, including menstrual irregularities and PCOS, can increase risk of CVD/CHD.

PUFAs against CVD​

“There may be opportunities across the lifespan to decrease CVD risk by increasing EPA and DHA intakes, right from young to older age,” Hall asserted.

“There’s evidence that female tissue status differs from men’s over the life course,” she explained, highlighting a study​ which found higher DHA and lower EPA status in younger women and suggested a heightened LC-PUFA need compared with men.

She said this implies a higher conversion rate of EPA to DHA in women, with further evidence​ highlighting that oestrogen enhances this conversion in younger women.

What’s more, Hall drew attention to a study​ into PUFAs impact on CHD incidence which suggested a gender-specific affect in which the men appeared to show no reduction in CHD risk, whilst women had a 15% reduction.

She noted that previous studies investigating supplementation with EPA and DHA had drawn mixed conclusions over the years, with RCTs​ in the early 2010s suggesting no benefit to CVD risk.

However,  there were minimal women included in these studies and later large-scale VITAL​ and REDUCE-IT​ trials have highlighted significant benefits to CHD risk, utilising 0.85 g/d of EPA and DHA and 1.8g/d of EPA alone, respectively.

She concluded that more research is needed.

“At the moment we are not seeing any evidence that men and women are responding differently. But we don’t have any good evidence due to the low numbers of women included in the studies,” she said.

Regarding natural declines in oestrogen during menopause, she stressed: “Perhaps we should be considering the lowered conversion of ALA, DHA, and EPA during the menopause as another potential cardiovascular risk factor. So these women may have a heightened need for long chain n-3 PUFAS.”

Hall also noted that menstrual abnormalities have been found​ to increase risk of hypertension and CHD/CVDs, adding: “There are some RCTs to suggest that supplements may improve the severity of menstrual irregularities and reduce their risk of cardiovascular issues in later life”.

Furthermore, she highlighted evidence​ to suggest supplementation with ALA/EPA and DHA in women with PCOS helped to lower insulin, LDL cholesterol, and triacylglyceride levels, whilst also reducing the incidence​ of pregnancy complications such as pre-eclampsia by 63%.

Again, she said more studies were needed to confirm these associations.  

Mechanisms of action​

Explaining the benefits of long-chain n-3 PUFAs, Hall explained: “EPA and DHA act on many of the underlying causes of CHD. They are incorporated into membranes and so, can modulate heart function and lower risk of cardiac death. They can lower heart rate and improve electrophysiological indices.”

She drew attention to their additional mechanisms of action - improving vascular function, reducing blood pressure and inflammation, and reducing triglyceride levels to ultimately reduce the risk of coronary heart disease.

Sex-specific deficiencies

Furthermore, Hall noted that the National Diet and Nutrition Survey (2016/17) found that only 13% of females in the UK meet the government recommendations to consume 1 portion of oily fish per week, or 0.45g/d of LC n-3 PUFAs, suggesting that most women were at risk of suboptimal tissue EPA and DHA status.

She added: “In females aged 18 and under, only 4% were meeting the guidelines according to the dietary assessment data. The other age group of concern were the women of reproductive age, with three quarters not consuming a portion of oily fish a week.”