The recent study linking diabetes with dementia in people with mild cognitive impairment is just one finding; evidence also links an increase in Alzheimer risk in people who develop diabetes before the age of 65. And last year, researchers published a study in the journal Neurology that links obesity, high blood pressure, and a low HDL (“good”) cholesterol level with cognitive impairment. Can taking dietary supplements help? Let’s look at a few more this week.
Nattokinase. Nattokinase is an enzyme that is extracted from natto, a Japanese food that is made from fermented soybeans. Natto is a strong-smelling, sticky, cheese-like food that is often eaten with rice for breakfast in Japan. Natto contains protein and vitamin B2. Nattokinase is thought to help promote heart health by preventing blood clot formation and stroke, since it acts like a blood-thinner.
There’s also some indication that nattokinase may help prevent Alzheimer by dissolving amyloid fibrils and preventing amyloid plaque build-up in the brain. In a study published last year in the Journal of Agricultural and Food Chemistry, Taiwanese researchers found that nattokinase dissolved amyloid fibrils (much like it dissolved blood clots), potentially paving the way to use nattokinase in food or supplement-form as a possible treatment for Alzheimer. However, there isn’t enough information at this time to recommend taking nattokinase supplements. In addition, because nattokinase is a blood thinner, it could potentially lead to increased bleeding and shouldn’t be used by people who are taking blood-thinner medicine, such as aspirin or warfarin (brand name Coumadin). On the other hand, you might try eating natto if given the opportunity!
Green tea. Do you like green tea? If so, keep drinking it. In a Japanese study published in The American Journal of Clinical Nutrition, older adults (age 70 or older) who drank at least two cups of green tea every day were 54% less likely to have test scores that indicated cognitive impairment compared to the folks who drank less than three cups a week. Even the people who drank one cup of green tea four to six times per week were able to benefit: they were almost 40% less likely to have cognitive impairment than people who drank the tea less than three times per week.
However, green tea may not be able to take all the credit, especially since people were only asked once about their tea intake. Even so, green tea looks like it could be a winner in the brain health promotion department. An antioxidant in green tea, called epigallocatechin gallate (EGCG) seems to have an ability to block amyloid plaque formation by changing certain harmful proteins into harmless ones, at least in mice. According to researchers, humans would need about 1,500–1,600 milligrams of EGCG to benefit from the same effect seen in mice. One cup of green tea has about 180 milligrams of EGCG, so one would probably need to drink about 10 cups of green tea per day. Once again, it’s important to realize that significant studies haven’t as yet been done with humans, so it’s wise to be cautious. But since green tea has other health benefits, a few cups a day may do the body good!
Acetyl-l-carnitine. Carnitine is a nutrient that the body uses to turn fat into energy. It’s made in the liver and kidneys and stored in the muscles, heart, and brain. For the most part, the body makes all the carnitine it needs, but certain health conditions, such as angina (chest pain), can lead to insufficient amounts. Acetyl-l-carnitine (ALC) is a form of carnitine that is fat soluble and active in the body’s nervous system. It’s thought that ALC might help block the formation of amyloid plaque in the brain, which, as I mentioned above, is a culprit in Alzheimer. And, it’s possible that ALC helps the brain metabolize fat and cholesterol, making it less likely for these substances to accumulate in brain tissue.
Some small studies conducted in the 1990’s indicated that giving 2–3 grams of ALC daily for 6–12 months might slow the cognitive decline seen in Alzheimer. But then a larger clinical trial with ALC showed no difference compared to placebo (inactive treatment) in slowing cognitive decline. Subsequently, another study suggested that people with early-onset Alzheimer might benefit from taking ALC but again, a later study found no effect from taking the supplement.
L-carnitine is found naturally in some foods, including beef, pork, and lamb. ALC is l-carnitine with an acetyl group added that can be used in the formation of acetylcholine, a neurotransmitter. A typical dose of ALC is 500–2,000 milligrams per day. Taking high doses (5,000 milligrams or more per day) can cause diarrhea and body odor. People with angina, high blood pressure, and kidney disease should talk with their health-care provider before taking this supplement.
In conclusion, there doesn’t seem to be a magic pill that will prevent cognitive decline. Some supplements are more promising than others. Looks like we should stay tuned for further developments!