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Articles December 2015 Issue

Polyunsaturated Fat Levels Linked to Longevity

Fats from fish, vegetable oils associated with lower heart and mortality risk.

A new long-term study from Sweden bolsters the evidence that the type of fats you consume is more important for your health than the total amount of fats in your diet. (See the November Special Report, "Stop Worrying About Total Fat.") Rather than relying on sometimes-inaccurate self-reported food intake, the study actually measured blood serum levels of the most important types of polyunsaturated fats. Health outcomes were then tracked for an average of 14.5 years.

Among the more than 4,000 participants, age 60 when the study began, higher levels of EPA and DHA - the primary omega-3 fats found in fish and fish oil - were associated with lower risk of death from all causes. Women with higher levels of EPA and DHA also had a lower risk of developing cardiovascular disease. Men with the most linoleic acid - the main component of most liquid vegetable oils such as soybean and corn oil - were 41% less likely to die of all causes than those with the lowest levels.

"There have been signals suggesting foods and oils high in polyunsaturated fatty acids were good for the heart and good for the health," says Alice H. Lichtenstein, DSc, director of Tufts' HNRCA Cardiovascular Nutrition Laboratory and executive editor of the Health & Nutrition Letter. "The findings of this study reinforce the importance of choosing healthy fats."

IMAGE © THINKSTOCK

HEALTHY FATS: Various other studies have shown health benefits from consuming the polyunsaturated fats found in fish, many vegetable oils, and nuts (see box). The heart-health benefits of the omega-3 fatty acids EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) were first observed in the 1970s among the native Inuit populations of Greenland, who consumed lots of fatty fish and had low rates of heart disease. Linoleic acid has been in the spotlight more recently, with a study reporting that substituting it for saturated fat was associated with lower risks of heart disease events and death. (See the February 2015 newsletter.)

In this latest study, published in Circulation, scientists recruited 2,193 women and 2,039 men in Stockholm who were turning 60 years old. Blood samples were collected after overnight fasting and analyzed using gas chromatography. Although fatty acids in the blood serum were tested only once - which scientists acknowledged is a weakness of the study - other research has found little change in these measures over time among similar populations. Such measurements have also been found to closely correlate with types of dietary intake.

GENDER DIFFERENCES: Although the study found significant evidence of health and longevity benefits associated with polyunsaturated fats, the connections differed sharply by gender. Only the associations between EPA and DHA and mortality risk crossed gender lines. The cardiovascular benefits with those omega-3s was significant only in women, which researchers speculated could be due to differences in overall dietary patterns or fish intake. Only men had a beneficial association between linoleic acid and mortality risk, but that link was very strong.

A fourth polyunsaturated fat studied, the omega-3 alpha-linolenic acid (ALA) found in soybean and canola oils, flaxseed, avocados and nuts, produced even more puzzling results: Women with the highest ALA intake were actually at moderately greater risk of developing heart disease. Those findings are at odds with other research on ALA, and the Swedish scientists noted that serum measurements of ALA are less reliable than for other fatty acids. Higher ALA levels could also indicate greater consumption of ALA-containing margarines or spreads, which may have contained saturated fats and/or artificial trans fats.

Overall, Matti Marklund, PhD, and colleagues from Uppsala University concluded, "the results support current dietary recommendations to increase omega-3 polyunsaturated fats (EPA and DHA) and linoleic acid from fish and non-tropical vegetable oils, respectively."

The best approach, says Tufts' Lichtenstein, is to substitute foods high in polyunsaturated fats for those high in saturated fats.

Comments (6)

Is vegetable oil any good

Posted by: Reg Alabo | January 22, 2016 11:59 PM    Report this comment

what about olive oil? all literature has given it the highest ratings.

Posted by: joan rogers | May 16, 2016 10:01 AM    Report this comment

I've been wondering about Herring, especially in wine sauce. It's readily available, quite reasonable in price and keeps well in the refrigerator. It does contain a considerable amount of sodium I've taken to eating the herring for lunch with plain boiled potatoes, to compensate for the extra sodium.

Posted by: Mary Richie | May 16, 2016 10:16 AM    Report this comment

Omega 3's can be had thru flax seed and chia seeds and other sources besides oils. Much has been written about the dangers of oils, not just the high caloric content but other serious dangers. For clarification on dangers of oil Google websites of Dr. John McDougal, Dr. Caldwell Campbell, Dr. Caldwell Esselstyn, Dr. Michael Greger (nutritionfacts.org) et al and search "oil".
Dr. Esselstyn of the Cleveland Clinic in his studies has prevented and in some cases reversed heart disease and is a big proponent of no oil. I know, hard to do, but i prefer my heart healthy. Plenty of other sources of fats to satisfy that jones, like seeds and nuts, etc.

Posted by: K Walden | December 19, 2016 10:45 AM    Report this comment

Olive oil primarily consists of oleic acid, a monounsaturated omega-9 fatty acid (roughly 70% of the fats), linoleic acid (mentioned in this article; about 15%) and palmitic acid, a saturated fat (about 13%). So, while olive oil has some nutritional benefit and offers some health benefits as well (likely due to its polyphenols), I don't think it would not contribute much to the effects seen in the study reported in this article based on the association of levels of omega-3 fatty acids, EPA and DHA and improved health outcomes.

Posted by: Unknown | December 19, 2016 1:16 PM    Report this comment

VIEW 2 DIFFERENT BRANDS OF SAFFLOWER OIL.

1= POLY 10 G., MONO 3 G.

2=POLY 3 G., MONO 10 G.

which is preferred oil??????????????????

Posted by: jack vitello | January 9, 2017 11:15 AM    Report this comment

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