Heart failure is a prevalent public health issue in countries where there is an ageing population, such as Japan.
Researchers from several Japanese universities therefore conducted a study to assess the link between dietary intakes of the fat-soluble vitamins A, D, E and K, and the morality rate in heart failure patients in Japan.
They recruited 23,099 men and 35,597 women between the ages of 40 and 79 to participate in the Japan Collaborative Cohort Study, and to complete a questionnaire on their food frequency, so they could calculate their intakes of the four vitamins.
During the median 19.3-year follow-up period, 567 (240 men, 327 women) participants died from heart failure.
The researchers estimated the sex-specific risks of death from heart failure and found it to be unrelated to dietary vitamin A intake in both sexes.
However, when it came to the consumption of vitamins D, E and K, a lowered risk was observed, but only in women.
They added that the association between the intake of each vitamin and the risk of death from heart failure "was slightly attenuated but remained statistically significant after mutual adjustment for intakes of the other vitamins".
This led them to state that high dietary consumption of the fat-soluble vitamins D, E and K was linked to a lower risk of death from heart failure in women but not in men.
In terms of limitations, they wrote: "The use of death certificates to ascertain heart failure deaths in the early years of the study (i.e., prior to 1994) was questionable, because most deaths of unknown origin, such as cardiac arrest or arrhythmic death — which are classified as ischaemic heart disease deaths in the United States — were registered as due to ‘unspecified heart failure’ in Japan.
"This classification accounted for 27% to 50% of diagnosed heart failure cases. Accordingly, the number of heart failure deaths in this study was contaminated by a number of cardiac arrest deaths and may have affected the association between dietary intakes of fat-soluble vitamins and heart failure."
However, they also said that sensitivity analyses to exclude deaths from heart failure had occurred within a decade of the follow-up period showed similar links.
They concluded: "In this large, community-based, prospective cohort study, higher dietary intakes of fat-soluble vitamins (K, E, and D) were associated with a reduced risk of mortality from heart failure among Japanese women but not men."
"Dietary intakes of fat soluble vitamins as predictors of mortality from heart failure in a large prospective cohort study"
Authors: Ehab S. Eshak, et al.