The most expensive real estate in the world is not Monaco, and it’s not Hongkong. It’s a piece of property roughly the size of two fists, and it’s all yours. It’s your brain. Your brain takes up just 2 % of space in your body, but it corners up to 30% of the calories you ingest. And up to half the oxygen supply available to your body.
But that’s really no big deal for an entity of such epic complexity. Quite simply, there is nothing in the Universe as complex as the human brain. Nothing. It’s estimated we have a hundred billion nerve cells in our brain and each nerve cell is connected to other nerve cells, not in a 1-to-1 connection, but up to 10,000 individual connections between cells....which means you have more connections in your skull than there are stars in the Universe.
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With such a magnificent machine operating every single activity of your body, it makes good sense to nurture it lifelong. Yet most of us take our brain for granted, and take less care of it than we do of our teeth. Not a wise strategy because, as we now know, the brain’s chemical messengers, which are crucial to all our mental functions and skills, are formed from substances catalysed from the foods we eat and the hormones our bodies produce.
Since at least the 1970s, scientists have known that certain nutrients are essential to human brain function, and that serious deficiencies in some of these can lead to impaired cognitive skills. And, charged by the thrill of the till, the food industry has leaped on to the bandwagon. Listen to the buzz about super-foods and dietary supplements and you’ll believe they can do everything from sharpening concentration to enhancing memory and boosting attention span.
Can they? A clear-cut answer would greatly affect the steadily-growing 50-plus population in particular. Their independence, quality of life, and even economic status, will be largely defined by their ability to traffic information signals as they age.
The science of nutrition and brain function is relatively new and evolving. While we have several insights into the kind of foods that may help prevent or slow down brain decline, we still don’t have pivotal proof in many key areas. All the same, certain common denominators are emerging, and here’s a look at some of them:
Fish and the Omega-3 Fatty Acids
Fish has had a reputation as “brain food” as far back as most of our memories go. Many modern-day scientists are endorsing that belief, elevating it above the status of an old wives’ tale. Certain fish – the same varieties that have been promoted as heart-healthy choices, in fact – have been claimed, in some research reports, to boost memory function by 15 to 20 per cent, and even to cut the risk of Alzheimer’s. The fish that are said to make the cut are those rich in omega-3 fatty acids; they include oily fish like mackerel (bangda/ayala), Indian salmon (rawas/kora/kaala), sardine (pedvey/chaalai/mathi), tuna (chura or toona machli), anchovy (kati/kozhuva), herring (bhing).
But, is the recommendation premature? Scientific studies, to date, have zeroed in on some promising indications:
» Some research has found that people whose diets were high in omega-3 fatty acids had lower blood levels of beta-amyloid, the tell-tale protein that gums up brains in Alzheimer’s patients.
» Imaging scans have shown that those who reported eating fish regularly were less likely to have brain cells die off in the area responsible for short-term memory – recalling a phone number that was just heard, for example.
» One of the largest population studies, covering 15,000 older people in 7 developing countries (including India), found that, as the reported fish consumption increased, dementia rates were progressively lower.
The scientific surmise is that oily fish appear to have a protective effect against dementia because the Omega-3 fatty acids they contain have anti-inflammatory properties. In animal studies, these fatty acids have been shown to reduce the build-up of atherosclerotic plaque (i.e., plaque in the arteries), and may also prevent the accumulation of amyloid plaque in the brain characteristic of Alzheimer’s.
But all the studies cited above were so-called “observational” studies. That is, the researchers simply observed behaviour in a systematic manner without attempting to influence the behaviour. In these studies, therefore, the findings on the fish-brain connection are based on people’s self-reports of how much fish they consumed; the scientists did not attempt to modify their subjects’ diets to see, for example, whether increasing intake of fatty fish translated into better mental function.
In contrast to these “observational” studies are the so-called “gold standard” studies, those that have randomly assigned people to take either omega-3 supplements or a placebo (a dummy pill) and then tracked the participants’ brain function over time. In the last few years, we have had some of these gold-standard studies, too. Disappointingly, however, the results have been mixed.
A research review by the Cochrane Library has also raised doubts about probable cognitive benefits from a diet rich in omega-3. Cochrane reviews have won acclaim as an excellent way of pulling together high-quality scientific evidence. The omega-3 review looked specifically at three “gold-standard” studies which together covered over 3,500 people, age 60 plus, who took omega-3 supplements for periods ranging from 6 to 40 months. While concluding that their analysis suggests there is currently no evidence that omega-3 fatty acid supplements provide a benefit for mental function in later life, the researchers did however add these caveats:
» One, it’s possible that the cognitive benefits of omega-3s may take longer than a few years — longer than the studies included in the review lasted — to show up. Cognitive decline may take several years to develop, so further research is needed to suss out the longer-term effects of omega-3 supplementation.
» Two, it’s also possible that taking omega-3 supplements may help only those who are low in the fatty acid to start with, while offering less benefit for those who already get enough in their regular diets.
» There is also the question of whether omega-3s from supplements are as bio-available as those coming in from natural foods like oily fish. “Bio-availability” essentially refers to how much of an ingested substance actually ends up being absorbed by our bodies.
The scientific consensus, for the present time, is that longer-term studies need to be carried out for more conclusive results.
Those scientists on the side of the believers recommend, for adults, at least two servings a week of omega-3-rich fish (a serving being roughly the size of a deck of cards).
You might decide there’s no harm done – and may be some very real benefits to be derived – from starting (or continuing) to include oily fish in your diet. And you would be right, if only for this reason: omega-3s have already won their spurs in lowering heart-disease risk as well as high blood pressure, and your heart health very directly impacts the health of your brain. Research in both, mice and humans, has found that when the brain doesn’t get enough glucose – as might occur when heart disease restricts the blood flow to the brain – a process is launched that ultimately produces the sticky clumps of protein that appear to be a cause of Alzheimer’s. This is a slow and insidious process which happens over many years. The finding is significant because it suggests that improving blood flow to the brain might be an effective approach to prevent or treat Alzheimer’s.
But don’t expect results overnight. It takes six months for the body’s tissues to get saturated with omega-3s.
While fatty fish are the very best source of omega-3 acids, these fats are found (in much smaller quantities) in a variety of other foods, too, including walnuts, spinach, pumpkin seeds, soyabeans and soyabean oil, canola oil, wheat germ, mustard greens (sarson ka saag).
Hurrahs For Haldi and the Anti-oxidants
The maturing brain tends to become vulnerable to two partners in crime: oxidative stress and inflammation.
Oxidative stress is thought to be brought on by the so-called free radicals. Free rads are not political rebels released from their prison cells. They are rogue molecules formed as a result of physical exertion, digestion and other activities of daily living which result in oxidation. Unless neutralized, free radicals can cause cellular damage (or “oxidative stress”). Our bodies have defense systems that keep these rogue molecules in check, but they’re not 100 per cent effective. And the brain’s cells are thought to be especially vulnerable to oxidative stress.
A second threat to the aging brain comes from inflammation. Chronic inflammation can pre-dispose the brain to develop Alzheimer’s disease. Whenever there is any brain injury (e.g., from concussion, contusion, hematoma or other causes) the brain’s unique immune cells (called microglia) rush to the site to repair tissue and prevent further damage. But chronic activation of the microglia causes them to secrete substances that hasten the progression of Alzheimer’s.
Oxidative stress and inflammation: two powerful foes that undermine brain function into the twilight years. What do we have to bolster the body’s own defenses against these threats?
Well, we have haldi. And we have cloves and cinnamon, cumin seed and nutmeg, mustard seed and red chillies, nuts and berries – in fact, a whole range of plant foods with a significant protective effect against both, free rads and inflammation.
Who hasn’t, by now, heard of the anti-oxidants? Their distinctive ID is the rainbow hues they flaunt: the deep red of tomatoes and of cherries; the orange of carrots; the yellow of corn, mangoes and saffron; and the blue-purple of Indian blackberries (jambul), blueberries and grapes. Among nutrients, those with the highest anti-oxidant values are vitamins A, C and E; and beta-carotene (which the body converts into Vitamin A).
Anti-oxidants have been studied for their effects on various bodily processes, including healthy brain function. Here’s a look at a few of the findings:
» In research on mice, those animals put on high-antioxidant diets from adulthood to middle age did not experience the age-related cognitive performance losses seen in control rats fed standard chow.
» In other research, a group of mice had their genes tweaked to produce a mutation that would cause an increase in amyloid beta, a prime culprit in Alzheimer’s. Half of these brain-plaqued mice were fed a diet high in blueberry extract for 8 months. The other half of the group was fed standard rat chow, and so was a control group of mice that didn’t carry the amyloid-plaque mutation.
At 12 months — early middle age in rats — all three groups were tested for their performance in a maze (which involves spatial memory). The brain-plaqued mice that were fed the blueberry extract performed as well as the healthy control mice and performed much better than their brain-plaqued peers fed standard chow.
Another finding was that the brain-plaqued rats fed on blueberry extracts also had increased growth of new brain cells (called ‘neurogenesis’). Neurogenesis plays a role in the formation of new memories. The brain’s capacity to produce new cells is thought to be greatly diminished during aging. But this study showed that anti-oxidants can give the brain a heave-ho that spurs the process.
All of which brings us back to the spice that is steadily forging ahead as a potent weapon in our arsenal against brain decline. Can we think of an Indian meal where turmeric (haldi) does not assert its distinctive bright yellow presence? In its anti-Alzheimer’s avatar, turmeric seems to work like a Swiss army knife. Its active compound, curcumin, is not only a powerful anti-oxidant, it’s also a powerful anti-inflammatory, and it helps to clear away the beta-amyloid plaques that are Alzheimer’s thumbprint. More? Curcumin also decreases the level of toxic metal build-up, another suspect in Alzheimer’s. And it inhibits the formation of cholesterol in the blood, attacking yet another culprit linked to beta-amyloid plaque. Over 1000 scientific studies have been so far conducted on the powerful health benefits of curcumin – in test-tubes, in rats and in humans.
So, what are we waiting for? Specifically, larger-scale human studies that are required to identify the therapeutic effects of curcumin. Also, several unanswered questions remain: What is the chief chemical property of curcumin that can be exploited in preventing Alzheimer’s? What is the role of curcumin in other brain disorders such as Parkinson’s and Huntington’s? Would it be more effective when used alone or with anti-inflammatory drugs?
Interestingly, studies have found that curcumin has its beneficial effects on the brain only at low doses. This is good news since it suggests that curcumin is most effective at doses well below pharmaceutical strength. May be pill-popping won’t be called for: just everyday Indian cuisine, co-starring turmeric – as it has done for thousands of years.
WHEN LESS IS NOT MORE: Vitamin and Mineral Deficiencies
Scientists know that certain nutrients are essential to human brain function. The ageing brain is particularly vulnerable to deficiencies in two B vitamins: B12 and folate. When there is a shortfall of these B vitamins, there is a build-up in the levels of homocysteine, a prime suspect in the processes leading to dementia.
Seniors are especially vulnerable to a gut disorder (atrophic gastritis) in which there is a thinning of the stomach lining, leading to poor absorption of B12 by the small intestine. That is why the recommendation is for those aged 50 plus to take vitamin B12 as a supplement.
Research also finds that people who eat foods high in folate have better memory and thinking skills as they age. On the other hand, several studies point to a link between low blood folate and depression – and depression is already known to affect brain function. Sources for folate include leafy green vegetables, ladies’ fingers, citrus fruits like melons, oranges and lemons, legumes (dried beans and peas), cereals, mushrooms, organ meats (e.g., liver, kidney). Also: foods fortified with this vitamin, and supplements. (Folic acid is the synthetic form of folate).
Iron. Earlier studies had already linked iron overload in adults with brain damage. But more recent research gives a new and unexpected twist to the iron deficiency-brain function link. This research has found that teenagers who show iron deficiency tend to be at higher risk for conditions that negatively affect brain function later in life. The risk, they found, was mostly in dementias such as Alzheimer’s. In fact, iron deficiency in the teen years led to an actual change in brain structure by early adulthood, the research has found. This link has been hinted at for some time now, but studies are beginning to actually demonstrate it.
The mechanism by which this happens is not well understood, but researchers stress that the link seems stronger than scientists expected to see. Especially because all the participants were young and healthy, and none of them, according to the researchers, “would have been catalogued as iron-deficient”. They concluded: “This is one of the deep secrets of the brain. You wouldn’t think the iron in our diet would affect the brain so much in our teen years. But it turns out that it matters very much. We found that healthy brain wiring in adults depended on having good iron levels in your teenage years.” When this finding is correlated with the fact that iron-deficiency is one of the most widespread health problems around the world, and certainly so in India, this research assumes added significance.
(The author, a former editor of 'Health & Nutrition' magazine, now works as a counseling therapist)