7: Making Sense of Vitamins and Minerals, Brain Food
HAVE YOU BEEN TAKING YOUR VITAMINS?
Vitamins play an essential role in our brains’ activity, growth, and vitality. Although they are not a source of direct energy, vitamins assist the brain in energy production. More specifically, they provide the key the brain needs to unlock the energy stored in the foods we eat and to activate a variety of metabolic processes that would be in danger of failing in their absence.
The importance of vitamins in relationship to optimal health has been understood by healers throughout recorded history and has long been a subject of scientific study. In particular, the discovery of vitamin deficiencies was a stepping-stone toward the recognition that nutrient deficiencies are at the heart of so many diseases once thought unavoidable.
We now know that vitamins are crucial to boosting our immune system, for absorption and elimination of other nutrients, and even more important, to produce neurotransmitters, the chemical messengers of the brain. As a result, several neurological diseases are made worse or even caused by vitamin deficiencies. Lack of vitamin B1 (thiamine) is implicated in degeneration of the nervous system (polyneuropathy) and in Wernicke-Korsakoff syndrome, a brain disorder that can evolve into dementia. Insufficient levels of vitamins B6 (pyridoxine) and B12 (cobalamin) also can lead to dementia. Deficiencies of vitamin B9 (folate) are known to cause neural tube defects of the fetus, leading to cognitive dysfunctions later in life. And the list goes on.
All these vitamins come from the foods we eat. Most vitamins cannot be manufactured in our brains or bodies at all, and therefore belong to the group of brain-essential nutrients that need to be obtained from our diet. When you eat fresh vegetables or fruits, the vitamins they release in the bloodstream travel all the way up to the brain, where they are received by their dedicated transport systems and are happily welcomed across the blood-brain barrier.
Vitamins are usually broken down into two categories: fat-soluble (i.e., dissolve in fat) and water-soluble (i.e., dissolve in water). They are further defined by chemical names and subtypes such as vitamin B6 or B12.
Fat-soluble vitamins include vitamins A, D, E, and K. An advantage of fat-soluble vitamins is that they can be stored in the fat of our bodily tissues and, as a result, don’t need to be continuously replenished. Among these vitamins, two are known for their brain-protective properties: vitamin A (via its precursor beta-carotene) and vitamin E. Both these vitamins have antioxidant functions that protect brain cells and tissues from the harmful effects of toxins, free radicals, and even pollution. Moreover, vitamin E increases delivery and absorption of oxygen into brain tissue, which is essential for optimal function and metabolic activity.
All other vitamins are water-soluble. Water-soluble vitamins cannot be stored and as such they are required daily in our diets. These include a number of vitamins that are essential for brain function, such as vitamin C, vitamin B12, vitamin B6, folate, and choline. In general, the major value of these vitamins is their ability to “make things happen.” They are the go-getters of the brain; their role is to facilitate the action of our neurotransmitters, sometimes even becoming part of a neurotransmitter itself. This is crucial for proper communication between brain cells. Choline is an example of how this all plays out.
CHERISH YOUR MEMORIES WITH CHOLINE
The brain depends on choline (a B vitamin) to manufacture the neurotransmitter acetylcholine. Acetylcholine is one of the main brain neurotransmitters, as it is crucial for memory and learning, as well as arousal and reward. If you or a loved one has Alzheimer’s, you have probably heard of how the memory loss typical of the disease is associated with a shortage of acetylcholine. Most available drugs for Alzheimer’s, like donepezil (Aricept), are aimed at improving the action of this chemical in the brain.
However, anyone can be low in this neurotransmitter because of their diets. Since choline is an essential nutrient that the brain needs but is not able to produce on its own, the production of acetylcholine is limited by how much choline is reaching the brain at any given moment.
Approximately 10 percent of the total amount of choline circulating in the body is produced by our liver. We must rely on our diet to provide the remaining 90 percent needed. For example, eggs are among the richest sources of choline. Eating a five-egg omelette nearly quadruples choline levels within a few hours, making this nutrient readily available to the brain for acetylcholine production. But if you are eating a diet deficient in choline, you will likely cause an acetylcholine deficiency in your brain—affecting your memory as the by-product. Unfortunately, as much as 90 percent of the American population is deficient in choline.
This begs the question: Is it easy to eat enough of this vital brain nutrient?
According to current dietary guidelines, if you are an adult woman, you and your brain need at least 425 milligrams (mg) of choline daily, while men need about 550 mg daily.
In practical terms, if you are an adult woman, you can get your 425 mg of choline by eating 22 grapefruits, or 3 pounds of broccoli, or half a chicken . . . or you can eat 3 eggs. If you are an adult man, you’ll need more of the same foods, so 27 grapefruits, 4 pounds of broccoli, 2 pounds of chicken, or about 4 eggs. Every day.
This is not to suggest that you should eat several pounds of broccoli a day (nor a case of grapefruit), but it does serve to clarify two very interesting things. First of all, it makes it clear that some foods are more choline-dense than others, and therefore more brain-supportive. For example, it’s easier to enjoy a three-egg omelette than to ingest twenty-two grapefruits. Second, this shows that eating right for your brain is both literally and figuratively “not a piece of cake.”
Let’s now take a look at the foods that best provide the choline necessary to boost our brains’ acetylcholine levels. As you can see in Table 6, egg yolks top the list, with a whopping 682 mg of choline per 100 grams of yolk (or about 4 eggs). Since stuffing yourself with egg yolks might be a tad impractical, a combination of different choline-rich foods is arguably the best solution. Other choline-rich foods include fish eggs (caviar), most fish, organ meat (e.g., liver, kidney, brain, and heart), shiitake mushrooms, wheat germ, quinoa, peanuts, and almonds.
|Food item||Unit (imperial)||Unit (metric)||Choline (mg)||Choline density (mg/100 g product)|
|Egg yolk, raw||1||20 g||136||682|
|Fish caviar||1 tablespoon||16 g||79||491|
|Brewer’s yeast||2 tablespoons||30 g||120||400|
|Raw beef liver||5 ounces||142 g||473||333|
|Shiitake mushrooms||1 ounce||28 g||57||202|
|Wheat germ||1 cup||240 g||202||84|
|Codfish||0.5 pound||227 g||190||84|
|Quinoa, raw||1 cup||170 g||119||70|
|Chicken||0.5 pound||227 g||150||66|
Table 6. Top ten food sources of choline. Food items are ranked by choline density.
As an additional assist, nutritional supplements can be helpful. Here’s a shortcut that might do the trick. Brewer’s yeast (the one that’s used to make beer, not to bake cakes!) is a great natural source of choline. Though an acquired taste for some, Marmite, a product that features brewer’s yeast as its main ingredient, is a regular staple in most English and Australian kitchens. Since first being manufactured in the early 1900s, this savory spread has been praised for its high nutritional value, so much so that it was included in every soldier’s rations during World War I. Considering it takes only a couple of tablespoons of brewer’s yeast to reach our daily choline requirements, sprinkling this food on cooked vegetables and salads, or adding to soups and stews, is a smart way to boost your choline levels. I always add some to my soups.
One word of caution: although it’s quite difficult to eat too many foods rich in choline, keep in mind that excessive choline can be toxic. In general, no more than 3500 mg for adult men and women is recommended as a daily dosage.
VITAMIN B6: THE PASSE-PARTOUT TO BRAIN ACTIVITY
As mentioned in chapter 5, the brain wouldn’t be able to produce neurotransmitters such as serotonin, dopamine, or GABA without the help of vitamin B6, so keep your B6 vitamin intake front and center. This vitamin must be obtained from our diet on a daily basis.
Vitamin B6 is widely available in many natural foods. As shown in Table 7, the best natural sources include sunflower seeds and pistachios, as well as fish (especially tuna), shellfish, chicken, turkey, lean beef, and organ meat. Other good sources can be found in sweet potatoes, avocado, leafy green vegetables, cabbage, bananas, and whole-grain products such as wheat bran and germ. Among all veggies, garlic is surprisingly rich in B6. A little more than 100 grams of garlic would provide all necessary B6 intake for the day. Unfortunately, 100 grams of garlic is equal to 40 fresh garlic cloves, which would be a challenge to ingest, not to mention what it would do to your breath. Vampires or not, that’s too much garlic.
Royal jelly (a more potent version of honey) is also a rich source. Personally, I take a teaspoon of royal jelly complete with bee pollen almost daily for their known (though perhaps not scientifically confirmed) natural antibiotic effects. Try drizzling it over yogurt, and top it all with chia seeds and crushed pistachios for a perfect serotonin-boosting snack.
Vitamin B6 supplements are also readily available in over-the-counter capsules or tablets. While toxicity is unlikely to occur from natural food sources, it is recommended that our daily intake of B6 not exceed 100 mg/day for adult men and women. So when using supplements, always keep an eye on the dosages.
|Food item||Unit (imperial)||Unit (metric)||Vitamin B6 (mg)||Vitamin B6 density (mg/100 g food)|
|Pistachios||1 cup||123 g||2.1||1.70|
|Garlic||6 cloves||20 g||0.22||1.10|
|Tuna||4 oz||113 g||1.18||1.04|
|Turkey||4 oz||113 g||0.92||0.81|
|Beef||4 oz||113 g||0.74||0.65|
|Chicken||4 oz||113 g||0.68||0.60|
|Salmon||4 oz||113 g||0.64||0.57|
|Royal jelly||1 teaspoon||5 g||0.05||0.5|
|Spinach||1 cup||90 g||0.44||0.49|
|Cabbage||1 cup||90 g||0.34||0.38|
Table 7. Top ten food sources of vitamin B6, ranked by vitamin B6 density.
MORE B VITAMINS: WHAT PROTECTS THE HEART PROTECTS THE BRAIN
Now let’s turn our attention to a substance called homocysteine. As doctors have long known, high homocysteine (hyperhomocysteinaemia) is a strong risk factor for stroke, which in turn is a major risk factor for dementia, accounting for as many as 25 percent of all cases.
Worse still, research shows that high homocysteine levels affect cognitive function even in people without strokes. Typically, in a lab test, homocysteine in the range of 4–17 mmol/L is considered safe. However, a study of over a thousand cognitively intact elderly who were followed for several years found that the risk of developing dementia was nearly doubled for those who had homocysteine levels of just 14 mmol/L at the study’s start. Even more stunning, an increase of only 5 mmol/L in homocysteine levels raised the risk of cognitive deterioration by another 40 percent. This indicates that our brains are more sensitive to this substance, and therefore to vascular changes, than previously imagined.
The good news is that high homocysteine levels are completely reversible. Not only that, one can achieve this simply by eating right. How?
The production of homocysteine happens to be regulated by specific B vitamins: B12 and folate (i.e., Vitamin B9) above all, in combination with the B6 mentioned earlier. When you don’t have enough of these B vitamins in your system, your homocysteine goes up and affects your circulation. When you do have enough, it goes right back down where it belongs.
A number of studies agree that adequate B-vitamin levels are protective against age-related cognitive decline. For instance, a study of one thousand people ages sixty-five and older found that those whose diets were rich in folate (more than 400 mcg/day) had a lower risk of developing dementia as compared to those whose diets were poor in folate (less than 300 mcg/day).
Similar results were observed for vitamin B12. Among over five hundred elderly participants, those who had low B12 levels (i.e., less than the DRI recommended dose of 2.4 mcg/day) had an increased risk of developing dementia as they got older. However, not even those whose B12 consumption was within normal limits were safe. The rate of cognitive decline for the average eighty-year-old who consumed the recommended dose of B12 was 25 percent higher than that of a similar eighty-year-old who consumed 20 mcg/day. Note that this is ten times the recommended dosage. Clearly, your brain needs more B vitamins than the rest of you.
It is very important to make sure that our brains have access to plenty of these B vitamins. Not only are they good for your brain at large, but they also have a firmly established role in the prevention of dementia. Recent randomized, double-blind, placebo-controlled trials (that all add up to very thorough trials) tested the effects of high-dose B-vitamin supplementation in a group of 85 patients with mild cognitive impairment (MCI), a condition at high risk for progressing to Alzheimer’s. Over a two-year period, the patients were treated with a combination of folic acid (0.8 mg/day), vitamin B12 (0.5 mg/day), and vitamin B6 (20 mg/day). At the end of the study, supplementation with these three vitamins had maintained memory performance and at the same time reduced the rate of brain shrinkage when measured via an MRI. The treatment was particularly effective for participants with high homocysteine levels. Their homocysteine went down to normal levels, and they also showed 53 percent reduced brain shrinkage.
Interestingly, the treatment’s success was also related to the patients’ consumption of omega-3 PUFAs. Those with high levels of omega-3s responded extremely well to B-vitamin supplementation. On the other hand, patients with low omega-3 levels before and during treatment did not show improvements, but rather showed the same brain shrinkage as the untreated patients. The moral of the story: make sure you consume plenty of omega-3s together with your B vitamins to maximize their combined efficacy.
These B vitamins are easy to obtain from a balanced diet. Many plant-based foods are rich sources of folate, especially black-eyed peas, lentils, spinach, tofu, and avocado. Vitamin B12 is found in shellfish (clams are the richest source) and fish (salmon, trout, mackerel, and fresh tuna fish top the list), as well as chicken, eggs, beef, and dairy products. Remember how a mere 3 ounces of wild salmon supply enough omega-3s for an entire day? Well, that same small piece of fish also contains three times the recommended daily dose of B12. Pair that with a fresh spinach salad and some avocado, and you’ve got a perfect brain-healthy meal.
In the end, just imagine that 25 percent of all dementia cases, and most likely some of the remaining 75 percent, might be fully prevented by increasing consumption of B-vitamin-rich foods. Ditto for strokes and vascular disease. It is hard to believe that after all this, some people still are not convinced that food is medicine.
THE BRAIN’S DEFENSE SYSTEM: THE ANTIOXIDANTS
Have you ever left an apple cut in two on the counter and noticed how it begins to brown? Were you to leave it there, it would darken further and begin to shrivel up. If it were in sunlight, this process would quicken even more—and should the environment be a polluted one, the entire process would accelerate further still. This sort of “rusting” effect is what we refer to as oxidation. Oxidation itself is a very normal process. It happens all the time to our brains, bodies, and many things that surround us—like apples left on the counter, or iron pipes left in the rain.
In the brain, oxidation happens whenever our brain cells burn glucose and oxygen to produce energy. And as you might guess, this is happening continuously. Generally, our brains manage to counterbalance this ongoing oxidation, but sometimes things get out of hand, and the amount of oxidation exceeds our brains’ ability to keep it in check. In that case, our brains suffer from what’s called oxidative stress. Simply put, oxidative stress is the damage made to cells as a result of prolonged oxidation and of the action of free radicals—harmful molecules that are also produced in the process.
Of all bodily organs, the brain is the one that suffers most from oxidative stress. Free radicals incessantly develop, thought by thought, making their way through our neurons like little tornados. The more free radicals your brain contains, the more damage done.
However, we are not defenseless. We can call upon antioxidants to protect our delicate brains. These substances are Nature’s way to prevent oxidation from happening in the first place. They have the capacity to wander throughout our bodies (brain included), fighting off whatever free radicals they encounter along the way. In simple terms, antioxidants are our police officers chasing away the bad guys.
Some antioxidants are produced by our body, but most are not and need to be obtained from our diet. In particular, vitamin E (from almonds or flaxseeds) and vitamin C (from citrus, berries, and a variety of veggies) are the body’s main antioxidant defenders. As an experiment, try sprinkling some lemon juice on that shriveled apple and watch how much longer the apple lasts.
It is important that we eat enough antioxidants to protect ourselves against brain aging and disease. Large-scale studies in the United States and Europe found that those elderly who consumed at least 11 IU (16 mg) of vitamin E per day had a 67 percent lower risk of developing dementia as they got older compared to those who consumed 6 IU (4 mg) per day. Those who consumed the highest amounts of both vitamin C and E had an even lower risk. Studies estimated that we need 133 mg or more of vitamin C per day to provide our brains with optimal protection in addition to the 16 mg of vitamin E specified above.
In more practical terms, it just so happens that the spinach-avocado salad mentioned in the previous section is rich in B vitamins as well as vitamin E. Sprinkle it with lemon juice for extra vitamin C, et voilà. See how easy it is to eat right for your brain?
Overall, there is consensus that regular consumption of vitamins C and E, sometimes along with beta-carotene (a precursor to vitamin A found specifically in fruits and vegetables orange in color), reduces the speed at which our brain cells age, increasing longevity and lowering the risk of cardiovascular disease and dementia.
Yet current guidelines recommend we take much lower doses of these precious nutrients. Part of the problem is that, when tested in formal clinical settings, antioxidant vitamins didn’t turn out to be as miraculous as everyone had hoped. Vitamin E was the only one that showed potential for slowing functional decline in Alzheimer’s patients—but only at high doses of 2000 IU (1.3 grams) per day.
What was at first puzzling to many led to a revelation: antioxidant supplements don’t really work. We must obtain these nutrients from natural food sources instead. The truth is, in the studies mentioned, only those participants who obtained their antioxidant vitamins from foods showed lower rates of cognitive decline and dementia. Those who relied on supplements to get their antioxidants had the same chance of developing dementia as those who consumed little to no vitamins.
Vitamin E is a great example of why this happens. The vitamin E found in synthetic supplements is composed of only one of the eight natural forms of this vitamin (alpha-tocopherol), while food itself provides combinations of all forms. This seems to reduce oxidative stress and inflammation to a greater degree than alpha-tocopherol alone. Pair that discovery with the fact that pills aren’t a particularly delicious meal, and it only makes sense to consume your antioxidants from fresh, vibrant foods such as high-quality vegetables and fruits, as well as nuts and seeds.
THE WONDROUS WORLD OF FLAVONOIDS
As you might remember from chapter 1, plants produce a vast array of chemical compounds called phytonutrients. Sometimes referred to as “vitamin P,” these substances serve a very specific purpose. Their job is to fight oxidative stress and inflammation, thereby increasing the life of the plant itself. They are usually produced in combination with various antioxidant vitamins and are particularly concentrated in the berries of the plant. As it turns out, plants aren’t the only ones benefiting from these compounds. By eating these berries, we, too, receive all the benefits of the plant’s effort to “live long and prosper.”
Scientists have identified and categorized more than four thousand phytonutrients, such as flavonoids and phenols. Common examples are the quercetin found in apples, the flavanols found in cacao beans, and the resveratrol that gives red wine its good name—each renowned for their superior anti-aging properties. While scientists have historically overlooked these substances, new experimental studies suggest that phytonutrients play a greater role in human health than previously thought. In the next chapters, we’ll see how they make up the heart and soul of those diets proven to promote health and longevity worldwide. Meanwhile, let’s talk about minerals.
MINERALS: A LITTLE GOES A LONG WAY
Besides vitamins, the brain loves mineral matter—earth-derived minerals that we primarily absorb from fruits and vegetables. Minerals are in fact remains of plant and animal tissue contained in the soil. “Ashes to ashes, dust to dust” refers to this very process. Minerals contained in the soil are absorbed by plants as they grow during the natural process that recycles these elements as nutrients in our foods.
Much like vitamins, minerals are essential to our physical and mental health. They lend structure to our cells, particularly our blood, nerve, and muscle cells, as well as to those that form our bones, teeth, and soft tissues. Minerals also serve many functions specific to the brain. Some function as electrolytes to help regulate brain fluids and hydration. Others power our metabolism. Others yet have the very important task of regulating nerve transmission. Magnesium, zinc, copper, iron, iodine, selenium, manganese, and potassium are each essential in keeping our brains healthy and active as we age.
But it isn’t only mineral deficiencies that are harmful to the brain. An excess of some minerals, especially in the form of metals, can be toxic to the brain when absorbed in high concentrations. These are primarily lead, cadmium, and mercury, which are known as heavy metals. Poisoning can easily occur as a result of industrial exposure, air or water pollution, foods, medicines, improperly coated food containers, or the ingestion of lead-based paints. Arsenic, another toxic metal, is used in the manufacture of pesticides and given as an antibiotic to farm-raised animals like chicken (which is unfortunate, as we end up ingesting the poison when we eat the chicken). Nickel is used in the manufacturing of the trans-saturated fats used to make margarine and soft spreads. You might want to check your toothpaste, too. There’s a good chance it contains titanium. A seemingly harmless material like aluminum also poses a major threat to our delicate brains. It’s long been known that aluminum is toxic to brain cells, even in small amounts. Yet we are all easily exposed to this metal by using aluminum containers and several types of cosmetics and medicines, and even by drinking purified water.
While symptoms and physical findings vary according to the metal accumulated, metal poisoning affects the activity of cells in the entire nervous system, in severe cases leading to brain inflammation (encephalopathy), which is often irreversible. Heavy metal toxicity is therefore one of the biggest threats to brain health in our society because of the unrestricted use of these elements for industrial purposes as well as a generalized indifference to the way we treat the planet. However, other more common and far less dangerous minerals can also damage the brain if ingested in excessive amounts. These are iron, copper, and zinc.
In adequate concentrations, these minerals are essential for optimal brain function. Iron is crucial for production of hemoglobin (the part of our blood cells that carry oxygen) as well as of some proteins. Copper is key to enzyme function and the health of our immune system, blood vessels, nerves, and bones. Zinc is one of the most important metals when it comes to supporting brain metabolism. We can all imagine just how easily deficiencies in any of these minerals would affect our brainpower and mental sharpness.
A common medical condition called anemia is a good example. Anemia develops when your blood lacks enough healthy red blood cells or hemoglobin. This is typically due to iron deficiency. Some of the first symptoms of anemia are fatigue, dizziness, weakness, loss of stamina, and brain fog, which would have an obvious impact on our ability to perform physically and intellectually.
Fortunately for us, it takes very little iron to reach adequate levels. On the other hand, most people err in the opposite direction, ingesting too much of this nutrient, which is toxic in excess. Make note: too little iron will make you anemic, but too much can harm your brain. This goes for copper and zinc as well.
Some studies have suggested that overconsuming iron, zinc, and copper might contribute to cognitive problems in the elderly. Excessive intake of these minerals promotes oxidative stress, that sort of “rusting” effect that makes your brain age faster.
Copper is the one that seems to be particularly bad news for your brain. New research suggests that the copper we ingest just by eating the typical modern diet is enough to increase our chances of developing Alzheimer’s. Copper seems to reduce the brain’s ability to clear away toxic amyloid proteins before they form the plaques that are the hallmark of Alzheimer’s while encouraging the clumping of those proteins at the same time.
Yet this is nothing compared to the copper ingested as part of a high-fat diet. Research shows that people whose diets are high in copper, saturated fat, and trans fat have particularly quickening rates of cognitive decline—roughly nineteen additional years’ worth of aging. In these studies, the copper intake that was ultimately associated with cognitive decline turned out to be harmful only among those people whose diets were high in saturated fat and trans fats at the same time. To make things worse, it takes very little copper for brains on a high-fat diet to go haywire—only 2.7 mg per day, which is the equivalent of a mere 3 ounces of ham.
But before we blame food in general for these effects, consider this. What is unknown to most of us is that copper also enters the body via other sources—by way of our drinking water, for one, when delivered via copper pipes. Further, many people absorb extra copper via vitamin supplements. Common multivitamins contain both copper and iron, sometimes even exceeding the recommended dosage. In short, if your diet is high in fat, you really need to watch your mineral intake, too, especially if it comes in the form of multivitamin supplements.
In the United States, we don’t even require these particular minerals in our supplements, as we consume plenty of these minerals from our everyday foods.