Power Foods for the Brain (11 page)

Note that the people in the Netherlands were within the range of what we would consider normal mental functioning. Even so, folate made a noticeable difference.

Researchers at Oxford University went a step further, testing folate, vitamin B
₆
, and vitamin B
₁₂
in older people who were having memory problems that were sufficient for a diagnosis of mild cognitive impairment.
⁹
As you will recall, that means they had significant forgetfulness but were otherwise fine for the moment. The researchers gave everyone a set of cognitive tests. Then, over the next two years, the participants started a
daily regimen that consisted of 800 micrograms of folate, 500 micrograms of vitamin B
₁₂
, and 20 milligrams of vitamin B
₆
, all of which are well above the recommended dietary allowances for these vitamins and more than one would typically get from foods.

The effects were remarkable. High homocysteine levels fell sharply, and many people found their memory improving significantly. Accuracy on testing was improved by as much as 70 percent. And brain scans showed that the B vitamins also helped protect against brain shrinkage over time.

Can these three vitamins prevent Alzheimer’s disease? That is not so clear. But studies of Alzheimer’s patients have shown that many have had excess homocysteine levels, suggesting that it is critically important to get the vitamins that eliminate it.
¹¹
,
¹²

Once people have been diagnosed with Alzheimer’s disease, vitamin supplementation has been disappointing. In a recent US study involving 409 people with mild to moderate Alzheimer’s disease, B
₆
, B
₁₂
, and folate supplements showed no benefits for the group as a whole. However, focusing on those whose symptoms were mildest, the vitamins did seem to slow cognitive decline over an eighteen-month period compared with people given a placebo.
¹³

Overall, these studies suggest that folate, B
₆
, and B
₁₂
help lower homocysteine, and that helps protect your memory. But before you start loading your shopping cart with supplement bottles, let me share some important caveats:

First, it is likely that benefits of vitamin supplementation will show up in people whose homocysteine levels have been too high as opposed to people with normal homocysteine levels.
⁸
,
¹⁴
It is easy for a doctor to check your homocysteine level. A value over 15 micromoles per liter is too high, and some clinicians would call for a more conservative cutoff of 13. If you are in the normal range, it is not necessary to get heroic amounts of these vitamins in your diet. Rather, you just want to make sure you’re not missing them.

Second, in the United States, many foods are supplemented with folate. If you are already getting plenty, more is not necessarily better. In fact, overdoing it with folate supplements may well be harmful. In the Chicago study, getting extra folate was not helpful and, if anything, increased the risk of Alzheimer’s disease over time.
¹⁵
Similarly, in a large Norwegian study, B vitamins were used in people who had recently had heart attacks to see if they could prevent recurrences. However, the study participants did not necessarily have high homocysteine levels, and B vitamins ended up doing more harm than good, boosting the risk of future heart problems by about 20 percent.
¹⁶

So what’s the safe and smart way to get the vitamins you need? Let’s take them one by one:

Best sources of folate:
Folate is in foods with
foliage—
that is, broccoli, spinach, asparagus, and other green leafy vegetables. You’ll also find it in beans, peas, citrus fruits, and cantaloupe. It is in all common multivitamin supplements, and, by law, many grain products in the United States are now fortified with it: bread, breakfast cereals, flour, pasta, and rice. The recommended dietary allowance for adults is 400 micrograms per day.

Folate is fragile. With processing and prolonged storage, the folate in foods gradually disappears. So fresh produce—and produce that is frozen quickly after harvest—is a good choice.

Best sources of vitamin B
₆
:
Whole grains, green vegetables, beans, sweet potatoes, bananas, and nuts are rich in B
₆
.
If these foods are part of your routine, you will easily meet the recommended dietary allowance. The recommended dietary allowance for B
₆
for adults up to age fifty is 1.3 milligrams per day. If you are over fifty, the RDA is 1.5 milligrams for women and 1.7 milligrams for men.

As you have noticed, greens and beans are good sources of both folate and B
₆
, so you will want to be sure to keep them on your shopping list and on the menu.

Best sources of vitamin B
₁₂
:
B
₁₂
is in fortified products, such as breakfast cereals or fortified soy milk, in all common multivitamins, and in B
₁₂
supplements. It is also found in animal-derived products, but the absorption from supplements and fortified foods is much better.

The recommended dietary allowance for adults is 2.4 micrograms. Most supplements have more than that, sometimes much more, and it is not toxic at higher intakes. The US government recommends that everyone over the age of fifty take a B
₁₂
supplement or choose B
₁₂
-fortified foods. My advice is that you not wait until you are fifty. A B
₁₂
supplement is essential for people who avoid animal products and an excellent idea for everyone else, too.

In 2009, a team of researchers in Singapore reported that people who had more vitamin B
₁₂
circulating in their blood had better memory function and better ability to pay attention. But they also found that B
₁₂
was especially critical in people with the APOE e4 gene.
¹⁷
Those with the APOE e4 gene who were low in B
₁₂
did badly on memory tests. But people with the APOE e4 gene who had higher B
₁₂
levels performed much better.

So why would anyone ever run low in B
₁₂
? Two reasons:

First, poor absorption. The vitamin B
₁₂
found in animal-derived products is bound to protein, and many people, particularly older people, do not produce enough stomach acid to
free B
₁₂
from the foods that contain it. Acid-blocking medicines, metformin (a common diabetes drug), and stomach disorders can reduce your absorption of vitamin B
₁₂
even further.

Second, diet. If you are skipping animal products (which is a very good idea), it is essential to have supplemental B
₁₂
, because foods from plants are devoid of B
₁₂
, except when they are fortified with it. That said, it is easy to find in B
₁₂
supplements and fortified foods.

Bottom line: Be sure to have folate, B
₆
, and B
₁₂
in your routine. I’d suggest emphasizing green leafy vegetables, beans, and whole grains, and also taking a supplement for B
₁₂
. They will work together to eliminate homocysteine, protecting your heart and brain.

By now, you have no doubt noticed that researchers are keen on fruits and vegetables. These healthful foods are loaded with important vitamins and other nutrients, as well as being strikingly low in “bad” fats.

Fortunately, many people share the researchers’ enthusiasm. Participants in the Chicago study who got three or four vegetable servings per day slowed their rate of cognitive decline by 40 percent compared with those who got only about one serving of vegetables per day.
¹⁸
Fruits and vegetables also help prevent stroke.
¹⁹
,
²⁰

Are some fruits or vegetables better than others? Are you better off having an apple or a serving of spinach? A team of Dutch researchers tackled that question by analyzing the diets of 20,069 healthy people and then following them for the next ten years to see which foods had the most health power. It turned out that orange fruits and vegetables had the most heart-
protecting power. People who ate the most carrots, sweet potatoes, cantaloupe, butternut squash, and their botanical cousins cut their risk of heart problems by 26 percent, presumably due to the beta-carotene and other nutrients in these foods.
²¹

When it came to preventing stroke, the real standouts were apples and pears.
²²
People who averaged the equivalent of an apple a day were able to cut their stroke risk by 50 percent or more.

But don’t focus just on carrots and apples. Go for the variety nature provides. As you walk into the produce section of a grocery store, you can’t help but notice the bright colors. The orange beta-carotene in carrots and sweet potatoes is a powerful antioxidant. The red color in tomatoes is
lycopene—
a cousin of beta-carotene and a powerful antioxidant in its own right. There are many others.

So by all means do have carrots and apples, and have many other fruits and vegetables, as well. It’s the generous variety of vegetables and fruits in your daily routine that does the trick.

While you’re in the produce section, pick up some berries. Yes, cranberry juice really does help prevent urinary infections, and blueberries may do the same. Many berry varieties contain antioxidants and other compounds that counter inflammation, and researchers have put them to the test for their effects on the brain. In a small study, researchers at the University of Cincinnati gave Concord grape juice to people with mild cognitive impairment and found that it improved their learning ability and modestly boosted short-term memory. The amount was roughly one pint of juice each day for twelve weeks.
²³
It was not necessary to drink it all at once; it could be divided into smaller servings.

The Cincinnati team also found benefit from blueberry juice.
²⁴
These studies were small, and it is not certain that other research studies will confirm their findings. Even so, berries and grapes are healthful foods that are rich in antioxidants with no harmful side effects.

In southwestern France, the river Garonne is flanked with vineyards that produce close to a
billion
bottles of wine every year. It is the wine capital of the world. In 2004, researchers in Bordeaux found that people who had a glass or two of wine each day were half as likely to develop Alzheimer’s disease compared with teetotalers.
²⁵
They were also less likely to develop other kinds of dementia, such as that caused by strokes.

Now, one might have been tempted to chalk up the findings to a local product promotion. But studies in the Netherlands and New York showed the same benefit—modest drinking cuts the risk of Alzheimer’s by about half.

Red wine is unusual in that the prolonged contact of the grape skins with the juice during fermentation lends a deep red color to the wine and also infuses it with bioactive compounds. One, called
resveratrol
, is being studied for antiaging and heart-protective effects. But when it comes to Alzheimer’s disease,
any
sort of alcohol seemed to produce the same benefit. It does not have to be wine. A modest intake of alcohol is known to help protect the heart, and it looks like it has the same effect on the brain.

But before you toast to health and longevity, let me offer a couple of caveats.

First, alcohol is not essential for health. People in Loma Linda generally avoid alcohol, because it is discouraged by the
Seventh-day Adventist Church. And yet they do extraordinarily well. In fact, it may be that alcohol’s role in other populations is simply to counteract some negative effect of a less-than-healthy diet. If you’re eating well, it’s not clear that alcohol adds anything.

Second, alcohol has risks. If you’re drinking more than about one to two drinks per day, you are at risk for liver disease, accidents, social problems, and several forms of cancer. In fact, the French government has been trying very hard for years to rein in the epidemics of cirrhosis and automobile fatalities that are caused by alcohol.

Even one drink per day—if it is every day—increases a woman’s risk of breast cancer. The explanation might be that alcohol interferes with folate. It turns out that the B vitamin that is important for eliminating homocysteine is also part of the body’s anticancer defenses, and alcohol disrupts its action.

Alcohol also increases iron absorption. While that may sound helpful, alcohol can contribute to iron overload, especially if you have more than two drinks per day.
²⁶

So, as you can see, alcohol’s effects are complicated and mixed. If you drink alcohol, the best advice is to have it modestly and intermittently as opposed to every day. And be sure to include plenty of greens and beans in your regular diet to give you the folate you need.

In 2010, a team of Finnish researchers found an unusual ally in the battle against Alzheimer’s disease: coffee. Over a twenty-one-year period, they tracked the coffee habits of a group of 1,409 people. Some loved it and others avoided it, like everywhere else. But the coffee lovers came out on top, with 64 percent less risk of developing Alzheimer’s disease. Even among
people carrying the APOE e4 allele, the effect of coffee was clear: a nearly two-thirds drop in their risk!
²⁷

That’s great news for coffee drinkers, needless to say. But there are two hitches. First, not every study agrees, although several previous studies did favor coffee, too. Second, only people who drank a lot of coffee—three to five cups a day—showed any benefit, and it looks like decaf doesn’t cut it.