Saturday, March 18, 2006

Blood pressure drugs cut Alzheimer's risk

Taking medications to lower blood pressure, particularly those known as diuretics, may be associated with a lower incidence of Alzheimer's disease (AD), according to a new study.

In a study of nearly 4,000 residents of Cache County, Utah, elderly individuals who were using antihypertensive medications at the beginning of the study were significantly less likely to have developed AD than those who were not at the end of the study, three years later. This relationship persisted when the researchers controlled for other factors, including gender, age, high cholesterol, diabetes and genetic risk.

When antihypertensives were broken down by type, diuretics were most strongly associated with a lower incidence of AD. More specifically, potassium-sparing diuretics, which contain additional components to preserve levels of the mineral in the body, were related to a more than 70% reduction in the risk of AD.

Beta blockers and antihypertensives known as dihydropyridine agents also were linked to a slightly protective effect against AD, while ACE inhibitors did not appear to be associated with the risk of developing the condition.

"Findings suggest that increased potassium levels may be associated with a reduced risk of dementia," study authors write. "Consistent with this idea are observations that low potassium concentrations are associated with oxidative stress, inflammation, platelet aggregation and vasoconstriction, all of which are possible contributors to AD pathogenesis."

That is a significant reduction, indeed.

  • We know that a high potassium diet protects against stroke and many small, undetected strokes may affect memory.
  • Adults should consume 4.7 grams of potassium per day. However, most American women 31 to 50 years old consume no more than half of the recommended amount of potassium, and men's intake is only moderately higher. African Americans generally get less potassium than whites, and because they have a higher prevalence of elevated blood pressure, increased potassium intake may have particularly significant benefits for them.
  • Potassium-sparing diuretics include Amiloride, Spironolactone, and Triamterene. These drugs are much weaker than the thiazides or the loop diuretics (potassium-wasting diuretcis). Even though they do not work quite as well, potassium-sparing diuretics do not reduce potassium levels nearly as much as other kinds of diuretics do. They may be used in combination with other diuretics, one example being Hydrochlorothiazide.
  • Diuretics can be used by themselves but many people with hypertension require more than one medication to effectively control their blood pressure. Because of this, diuretics are often put together into a single tablet or capsule with drugs from other classes of antihypertensives. For example, HCTZ has been combined with various ACE inhibitors, beta blockers, and angiotensin receptor blockers (ARBs). Examples include Avalide and Hyzaar.

This study indicates that while high blood pressure is thought to raise the risk of Alzheimer's, "the protective effects of these antihypertensive medications may be independent of their ability to control blood pressure." Maybe it's the potassium. Maybe, something else.

Eat like your ancestors - Up the Potassium!


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