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What stress and high-fat foods do to your blood vessels…It’s not good

Cardiovascular disease is the number one killer of Canadians representing 32% of all deaths in 2004. There are a multitude of risk factors for this disease including stress and fat consumption. While the independent effects have become more clear in recent years, the combined effect of both stress and fat consumption on blood vessel and thus, heart health is relatively unknown. This is important because experiences of stress and fat consumption often occur together in everyday life (e.g. donuts at a work meeting, or classic “comfort foods” like macaroni and cheese or ice cream).  Luckily, a fellow colleague and friend of mine, Veronica Poitras has dedicated a portion of her doctoral research to elucidating this very question.

The architecture of our blood vessels is quite fascinating. The endothelium is the innermost lining of the blood vessels and plays an integral role in vessel health. How? It exerts an anti-atherogenic influence. Many of you may be familiar with the disease coined atherosclerosis which is characterized by the build-up of fatty plaques in the arteries. It is a progressive condition, starting as early as childhood and is a major cause of heart attacks and strokes. An anti-atherogenic influence helps to prevent the build-up of these nasty plaques.

What is it about the endothelium that prevents plaque accumulation? It releases a molecule called nitric oxide (NO) which prevents components of the blood from sticking to vessel walls and building up to form plaques. In addition, NO acts on the smooth muscle in the blood vessel walls, causing it to relax and dilate (a very good thing for blood pressure). Blood vessel dilation is how researchers measure the NO responsiveness and thus, the health of the endothelium.

When we eat high-fat meals or experience stress our endothelium takes a beating. Impaired endothelial function can happen as soon as 1 hour after fat consumption with the greatest impairment at 4-6 hours after. In terms of the timeframe for an acute experience of mental stress, an impairment has been observed as soon as 10 minutes after and can last as long as 4 hours after (for only a 10 minute bout of stress)!

Independently, both these stimuli have been found to impair NO function (i.e. less production/release of NO in addition to an increased degradation/uptake). Simply stated, there is less NO actually kicking around to be able to exert its positive influence. However, how these two stimuli interact with one another is largely unknown. There is reason to believe that the combined effects of stress and fat consumption may be greater than the experience of either alone.  

In Veronica’s current study she will have participants consume a high-fat meal and expose them to various forms of acute mental stress. She will assess endothelial health (release of NO) by measuring blood vessel dilation using echo ultrasound to get an image of the artery. This will give her a fairly good indication of what is happening to our endothelium after acute exposure to these deleterious stimuli.

High-fat food consumption is a growing concern in North America. I’m not referring to the healthy fats found in dairy products, avocados, etc. I am referring to that found in processed foods. Oddly enough, when we’re stressed we often turn to such foods. From an evolutionary viewpoint, ingesting fat (i.e. a lot of energy) increased your chance of survival. This may partially explain our love and desire of fat (and sugar) when stressed.

Veronica’s research will help to increase our understanding about two primary risk factors for cardiovascular disease. This is powerful information. In the long run, this research may help to reduce the incidence of the number one killer of Canadians.

M  

I would like thank Veronica for her contribution and assitance in the writing of this post.

Image courtesy of Petit Plat Food Art – Stephanie Kilgast

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