Flaxseed and cardiovascular health
What the squeaky wheel gets
So it’s not a surprise that I’ve also been receiving a greater number of e-mails on the subject of oil. In particular, a couple of comments and questions about flaxseed oil have come my way, with members wondering about the cardiovascular health claims surrounding this remarkable oil and the best ways to ingest it.
We’ll begin this look at flax by first heading down to oil country: Stillwater, Oklahoma.
Flaxseed contains lignans, a fiber and phytoestrogen with a chemical makeup similar to human estrogen. Lignans are also a good source of alpha-linolenic acid, that is converted by the body into omega-3 fatty acids – compounds that help regulate several key cardiovascular functions such as heart rate, blood pressure, blood vessel dilation and blood clotting. So the Oklahoma researchers set out to study the cardiovascular effects of flaxseed on 36 postmenopausal women.
Half of the group ingested 40 grams of ground flaxseed daily for 3 months. The other half received ground wheat instead of flaxseed for the same period. At the end of the research period, the flaxseed group showed an 8% reduction in the blood level of apolipoprotein B – a molecule that carries cholesterol and is regarded as a better marker for heart disease than cholesterol alone. Total cholesterol levels of the flaxseed group also fell, but both LDL and HDL levels fell – in effect canceling out any benefit in the cholesterol department. The group of women who received the ground wheat showed no changes in cholesterol or apolipoprotein B levels.
As promised, these results are not earth shattering. But there is clearly something going on here, it’s obviously something good for the heart, and the primary active ingredient is omega-3.
An omega balance that favors omega-6 promotes inflammation and has a negative impact on the body’s immune system. We ingest omega-6 mostly through the consumption of corn, safflower, sunflower and (there it is again) canola oils – all commonly used in food processing.
The primary source of omega-3 is fish, especially dark-meat fish like salmon, swordfish and tuna. If you want to avoid mercury, a high quality fish oil supplement is a good source as well. Interestingly, both omega-3 and omega-6 are present in beef. But if the source cattle of your beef have been fed grain, omega-6 will be the larger balance, and if the cattle have been fed grass, omega-3 will prevail. Unfortunately, most of the commercial beef (especially in grocery stores) comes from grain-fed cattle. Even grass-fed cattle are usually fattened with grain feed in the days just before slaughter. (One member wrote to me last fall to suggest we buy only “grass-finished” beef.)
Another way to get the omega-3 benefits of flaxseed is to crush the seeds and eat them raw. Like the oil, the flaxseeds have a nutty taste, but at least two sources I found indicated that eating the whole seeds is not as beneficial as taking a spoonful of the oil. One of the things that flaxseed oil does best is to transport vitamin A (a fat soluble vitamin) to cells throughout the body, giving a boost to the immune system. Ingesting the seeds won’t have this same effect on vitamin A. In addition, the seeds contain a protective enzyme inhibitor that keeps them dormant until they meet optimal growing conditions. Apparently these inhibitors can sometimes be hard on digestive enzymes, resulting in gas and an upset stomach.
One important word of caution: While some studies have suggested that the alpha-linolenic acid in flaxseed and other plant oils may be helpful in slowing the growth of cancers of the breast and colon, a number of other studies have shown that alpha-linolenic acid intake may create an increased risk for prostate cancer. Based on these studies, men with prostate cancer, and those with elevated PSA levels, should not take flaxseed oil. And, while ground flaxseed delivers far less alpha-linolenic acid, it’s still better for those men to avoid the seeds as well. (I’ll mention again that this is Prostate Cancer Awareness Month and a perfect time to visit the web site “prostateforum.com.” It’s the first source I go to for information on prostate cancer health.)
Obviously the key to this particular oil issue is balance. So many of the processed foods we consume contain the culprit oils that deliver omega-6 that it’s probably a very good idea to add some salmon, fresh tuna, a fish oil supplement, ground flaxseed or flaxseed oil to our diets to provide the much needed protection of omega-3 in the balancing act.
To Your Good Health,
Jenny Thompson
Health Sciences Institute
