Insulin’s Effect on Blood Pressure

lower blood pressureFebruary 19th, 2010 – In a previous article, I talked about how high carbohydrate diets can increase triglycerides (blood fats), or high cholesterol. It also appears that high carbohydrate consumption can increase hypertension, or high blood pressure.  Check this out.

It’s not actually the carbohydrates doing the damage; rather it’s their corresponding hormone – insulin.  The more carbs we eat, the more insulin our bodies pump into the blood stream to shuttle the glucose into cells for storage.  When we are in a hyperinsulinemic (high insulin) state, like the one you’re in when you eat a high carbohydrate diet, the kidneys will retain more sodium than normal. (1)  This is the body’s protective mechanism to maintain proper electrolyte balance, by retaining water to keep the sodium sufficiently diluted.  More water leads to increased blood volume, and thus more pressure on the walls of the blood vessels.

Insulin also stimulates the smooth muscle cells of the arterial walls, acting like a growth hormone and causing them to enlarge and thicken. (2) As they grow, the interior space of the blood vessels decreases, which further increases blood pressure.  Combine narrowed vessels with increased blood volume and you have a perfect recipe for a heart attack.

References –

1. Insulin and renal sodium retention in obese adolescents.

Rocchini AP, Katch V, Kveselis D, Moorehead C, Martin M, Lampman R, Gregory M.

Hypertension. 1989 Oct;14(4):367-74  PMID: 2676858

2. Protein Power

Dr. Michael Eades

New York, NY: Creative Paradox LLC (2000)

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Carbohydrates Drive Up Cholesterol

Evil ToastOctober 16th, 2009 – Despite what your doctor and favorite fitness magazine tell you, dietary cholesterol is not the enemy. In fact, our own cells manufacture roughly 80% of the cholesterol in our body (1). Increase your dietary intake, and normally the body will compensate by producing less of its own. Decrease, and your body will make more.

So where do carbohydrates fit in to all of this?

When you ingest carbohydrates, they are broken down into glucose and released into the blood stream. This raises blood sugar levels, and the body releases insulin to deliver the sugar to the various cells in the body for use as fuel. Aside from storing nutrients in the body, insulin also stimulates the enzyme HMG-CoA reductase, which determines the rate and amount of cholesterol produced by our cells. (2) The more cholesterol our cells produce, the less they remove from the LDL particles in the blood, and the more cholesterol remains in circulation.

Take home message – It’s the toast, not the eggs.

References

1. Protein Power
Dr. Michael Eades
New York, NY: Creative Paradox LLC (2000)

2. Interaction between cholesterol and glucose metabolism during dietarycarbohydrate modification in subjects with the metabolic syndrome
Maarit Hallikainen, et al.
Am. J. Clinical Nutrition, Dec 2006; 84: 1385 – 1392.

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