Resveratrol May Help Prevent and Treat Alzheimer’s Disease

Recent studies suggest a glass of glass or two of Cabernet Sauvignon may be a good way to prevent Alzheimer’s disease.¹⁰⁷ And a whole host of population, lab, and animal studies indicate that resveratrol may be able to improve the symptoms of the disease as well, which is the primary cause of dementia.^108-109 In contrast to healthy aging, Alzheimer’s disease destroys large numbers of brain cells, beginning with areas that control memory, language, and reasoning but then continuing until the affected person becomes virtually helpless and nonresponsive.¹⁰⁹

Considered a growing burden around the world, Alzheimer’s usually only affects people over age 65 but it can occur in younger adults too.¹¹⁰ As of 2010, there were over 35 million people with Alzheimer’s disease—which is believed will rise to almost 66 million in the next 20 years.¹¹⁰ There are only a few pharmaceutical drugs approved in the U.S. to treat Alzheimer’s disease.¹⁰⁹ All inhibit the enzyme that breaks down the neurotransmitter acetylcholine, which is used by the brain when forming memories.¹⁰⁹ Although these drugs help counteract the cognitive losses associated with Alzheimer’s, they do not stop the disease from progressing or reverse brain cell loss.¹⁰⁹

With the costs to society running in the billions of dollars, the need to find and develop preventive and treatment measures is crucial.¹¹⁰ In the past decade most of the new drugs that have been developed inhibit the enzymes that produce the proteins that contribute to the brain lesions characteristic in Alzheimer’s disease.¹¹¹ However, recent research indicates that inhibiting these enzymes can cause severe adverse side effects, making the need for new and safer treatment options even more urgent.¹¹¹ To that end, clinical trials have begun on resveratrol to assess its usefulness with this progressive and debilitating condition.¹⁰⁸

How Does It Work?

The disease is characterized by two types of lesions in the brain which cause loss of connections between neurons and then cell death:¹⁰⁹

• Amyloid plaques: Accumulation of cellular debris in between neurons, consisting of amyloid beta protein fragments, parts of degenerating nerve cells, and other proteins.
• Neurofibrillary tangles: Abnormal clusters of the tau proteins, which are normally used to help support the tube-like structures inside neurons that are used to transport molecules between the nerve ends (axons) and the neuron cell body. These clusters are created when too many phosphate molecules attach to the tau proteins.

Lab studies show that resveratrol blocks damage from free radicals and other toxic substances and prevents the formation of amyloid plaques.¹¹¹ It appears to do so by indirectly stimulating enzymes that break up amyloid beta proteins, and not by inhibiting the enzymes that produce the plaques.¹¹¹ Results of recent animal studies suggest that oral administration of resveratrol may also improve cognitive functioning by stimulating production of insulin-like growth factor-I (IGF-I) in the brain.¹¹²

Evidence of Benefit

Lab and animal studies continue to document resveratrol’s antioxidant protective effects in the brain, as well as the ability to either inhibit or stimulate production of molecules (e.g., growth factors and neurotransmitters such as glutamate) which are beneficial to brain health and cognitive functioning.¹¹³ More than one population study has documented the link between drinking moderate amounts of red wine and lower rates of dementia, including Alzheimer’s disease.¹¹¹

Interestingly, animal studies indicate that oral consumption of high-dose resveratrol increases cognitive function even without detectable levels in the brain—suggesting that sensory neuron stimulation in the gastro-intestinal tract activates factors that improve brain cell function.¹¹² Studies done specifically using animal models of Alzheimer’s disease suggest that resveratrol can reduce neurodegeneration, prevent learning impairment, and inhibit plaque formation.¹⁰⁷

Although most clinical trials assessing the effects of resveratrol in humans have focused on safe dosage levels and its bioavailability, a few have studied resveratrol’s impact on diseases. In one study involving 24 healthy adults, resveratrol was found to help regulate factors that influence blood flow in the brain. In fact, single doses of either 250 or 500 mg of resveratrol showed more blood flow to the part of the brain that handles high level cognitive functioning than those study participants who received a placebo—demonstrating that resveratrol has a measurable beneficial impact on brain function. The effect was also shown to be dose-dependent, with greater blood flow linked to the higher dosage.¹¹⁴

Cognitive Problems Related to Diabetes

Diabetes promotes an abnormal increase in the activity of AChE (an enzyme present in the central nervous system) that can lead to cognitive memory impairment. Animal studies have shown that administering 10-20 mg/kg of resveratrol inhibited this enzyme increase and could potentially improve cognitive outcomes in diabetics.¹¹⁵

The deterioration of neurons which causes acute memory loss in Alzheimer’s disease is linked to insulin receptors on these cells, and in fact patients with Type II diabetes are at greater risk for this condition. Animal studies also suggest that diabetes may accelerate the cognitive losses associated with Alzheimer’s disease. Promising new research now indicates that medication increasing insulin sensitivity in these receptors can improve cognitive function and memory in Alzheimer’s and Type II diabetic patients. Since studies have shown that resveratrol increases insulin sensitivity, it could potentially be a therapeutic treatment for AD.¹¹⁶