Not All Fatty Acids Are Created Equal: New Study Links Fatty Acids and Increased Heart Disease Risk

By Tamara Thomas - Last Updated: November 10, 2023

Eating more trans-monounsaturated fats and conjugated linoleic acids may increase the risk of heart disease and stroke while cis-polyunsaturated fats may lower it, according to a study published in the American Journal of Clinical Nutrition

Atherosclerotic cardiovascular diseases (ASCVDs), including myocardial infarction, stroke, or angina, are the leading causes of death in adults. It is widely known that different types of dietary fats can affect your risk of heart disease and stroke, but it is not entirely clear how individual fatty acids play a role.

For this study, Dr. Kerry L. Ivey and colleagues sought to examine the relationships between the total fat classes and individual fatty acids with the risk of ASCVD.

The researchers obtained data from the Million Veteran Program (MVP), which has enrolled 702,740 veterans. However, this study focused on about 350,000 individuals who completed the MVP Lifestyle Survey and reported on their habitual dietary intake. After excluding participants with pre-existing conditions such as ASCVD or cancer, the final number of participants was 158,198. The average age of the veterans in the study was 61 years, and the average years of follow-up was 3-4 years.

In addition, the researchers assessed dietary intake using a validated Food Frequency Questionnaire, which asked participants about their average consumption frequency of 61 different foods over the previous year. Researchers then used this information to calculate the intake of 27 commonly consumed fatty acids and nutrients, expressed as a percentage of daily caloric intake.

The researchers observed that, on average, the participants derived 32% of their total daily calories from fats. They also noted that 11,771 ASCVD events occurred throughout the follow-up period. The most predominant ASCVDs observed were ischemic heart disease (IHD), ischemic cerebrovascular disease (ICVD), and peripheral arterial disease (PAD).

The study found that higher saturated fat intake was linked to increased ASCVD risk, even after adjusting for body mass index (BMI). Replacing saturated fats with cis-polyunsaturated fats reduced ASCVD risk. However, when considering specific ASCVD components, higher saturated fat intake was only linked to PAD, not IHD or ICVD.

The researchers further investigated the effects of individual saturated fatty acids. They found that a higher intake of butyric acid, a short-chain fatty acid, was linked to a lower ASCVD risk.

In contrast, increased consumption of margaric acid, found in dairy and beef fats, was associated with a heightened risk of ASCVD. Palmitic acid was also associated with an elevated ASCVD risk, but this association weakened after BMI adjustment.

For trans-unsaturated fatty acids, the study revealed that higher consumption of trans-unsaturated fatty acids was linked to a greater likelihood of experiencing ASCVD events, even after adjusting for BMI. This association was particularly strong for trans-monounsaturated fatty acids, increasing the risk of IHD and PAD.

For cis-unsaturated fatty acids, the researchers focused on oleic acid, the main component of daily cis-monounsaturated fat intake, and found no significant association with ASCVD risk. However, higher consumption of certain cis-unsaturated fats, such as palmitoleic acid and cis-vaccenic acid, corresponded to increased ASCVD risk. Participants with higher cis-polyunsaturated fat intake, especially linoleic acid, had a lower likelihood of ASCVD events.

Finally, the study found that most conjugated linoleic acid intake came from ricinoleic acid. Those who consumed the most ricinoleic acid were more likely to have ASCVD, particularly for IHD and PAD.

“Although higher intakes of specific trans-fatty acids and conjugated linoleic were associated with an increased risk of ASCVD, the same cannot be said for all other fat classes. This work suggests that care must be taken when drawing general conclusions regarding the health effects of dietary individual fatty acids,” the researchers concluded.

Source: Medical News

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November 30, 2023