By our seventies, one in five of us will suffer from cognitive impairment. Within five years, half of those will progress to dementia and death. The earlier we can slow or stop this process, the better.
Although an effective treatment for Alzheimer’s disease is unavailable, interventions to control risk factors could prevent millions of cases. An immense effort has been spent on identifying such risk factors for Alzheimer’s and developing treatments to reduce them.
In 1990, a small study of 22 Alzheimer’s patients reported high concentrations of homocysteine in their blood. Homocysteine is now considered “a strong, independent risk factor for the development of dementia and Alzheimer’s disease.” In the Framingham Study, for instance, researchers estimate that as many as one in six Alzheimer’s cases may be attributable to elevated homocysteine in the blood, which is now thought to play a role in brain damage and cognitive and memory decline.
As we age, our brains slowly atrophy, but the shrinking is much accelerated in patients suffering from Alzheimer’s disease. Our body can detoxify homocysteine using three vitamins: folate, vitamin B12, and vitamin B6. Researchers tried giving people B vitamins for two years and found it cut the rate of brain atrophy in half. They also discovered that B-vitamin treatment reduces by as much as seven-fold, the brain atrophy in regions specifically vulnerable to Alzheimer’s disease. Researchers have learned that B vitamins can slow the rate of accelerated brain atrophy in people with mild cognitive impairment too. The thinking is if we could slow the rate of brain loss, we may be able to slow the conversion to Alzheimer’s disease.
The best way to prevent cognitive decline is to not become deficient in B vitamins in the first place, especially B12, B6 and folate and thereby limit the amount of homocysteine in the blood.
Folate, which is concentrated in beans and greens, is a powerful reducer of homocysteine in the blood. Ninety-six percent of people don’t even make the minimum recommended amount of dark green leafy vegetables, which is the same pitiful number who don’t eat the minimum recommendation for beans.
If we put people on a healthy plant-based diet we can drop their homocysteine levels by 20% in just one week, from around 11 mmoles per litre down to 9 mmoles per litre. The fact that they showed rapid and significant homocysteine lowering without any pills or supplements implies that multiple mechanisms may have been at work. The researchers suggest it may be because of the fibre. Every gram of daily fibre consumption may increase folate levels in the blood nearly 2%, perhaps by boosting vitamin production in the colon by all our friendly gut bacteria. It also could be from the decreased methionine intake.
Methionine is where homocysteine comes from. Homocysteine is a breakdown product of methionine, which comes mostly from animal protein. If we give someone bacon and eggs for breakfast and a steak for dinner, we can get spikes of homocysteine levels in the blood. Thus, decreased methionine intake on a plant-based diet may be another factor contributing to lower, safer homocysteine levels.
But fibre and folate work together with B12 and other B vitamins. Vegans can suffer from higher levels of homocysteine than meat eaters if they don’t get enough B12 along with their high intake of fibre and folate. Vegans that take B12 supplements can drop their homocysteine levels to 5mmoles per litre. Once vegans got enough B12, they could finally fully exploit the benefits of their plant-based diets and come out with the lowest levels of all.
In conclusion, if you want a vigorous intellect even when you are old, a plant-based diet, naturally rich in folate and B vitamins, combined with good intake of B12, either through B12 rich plants, or B12 supplementation, provides all you need to reduce homocysteine levels in your blood.