Feed Your Head

by Melinda Safir, MS, RD, LD on May 01, 2007

How the right nutrients can keep your brain fit and flexible.

The idea that it is possible to better one’s health through a healthy diet may seem like a new notion, considering all the recent media reports on the topic. However, this hypothesis is nearly 2,500 years old, as evidenced by Hippocrates’ ancient advice to physicians to “leave your drugs in the chemist’s pot if you can heal the patient with food.” The fact that today’s emerging research has scientifically connected diet to disease prevention merely confirms what Hippocrates said way back then.

Although most of the studies to date have centered on the power of food to reduce cardiovascular disease and prevent cancer, diet can also have a profound effect on brain health. By nourishing your brain with the right foods, you can boost its levels of endurance, cerebration, acuity and cognizance, as well as its overall mental reserves. As we examine the latest research on protective brain foods, you will learn the best diet to support your brain’s functions, along with some sure-fire strategies to maintain your wits for a lifetime.

How Food Fuels the Brain

First, let’s take a look at that 3-pound mass of tissue we call our brain. The brain acts as the control tower for the body and the mind, containing as many nerve cells, or neurons, as there are stars in the Milky Way galaxy. Known as the primary functional units of the brain, these neurons “talk” to each other across fluid-filled junctions, or synapses, between the cells. These specialized delivery messengers are called neurotransmitters.

Neurons expend about 20% of the total energy consumed by the body each day (Raichle & Gusnard 2002), and nerve transmission across the synapses accounts for one-half of that expenditure (The Franklin Institute Online 2004). The neurons are continually firing as they gather and dispatch much-needed information to the rest of the body, while also coordinating the activities required to perform specific body needs. With all this activity, it’s no wonder that the brain is extremely active metabolically, making it hungry for fuel.

To support its high level of activity, the brain demands a continuous sugar fix. Glucose is its preferred energy source. Even while the body is at rest, the brain uses more than two-thirds of the carbohydrates circulating in the bloodstream (The Franklin Institute Online 2004). Consuming a diet rich in complex carbohydrates will provide a slow and steady release of energy, which is ideal for fueling a healthy brain.

Several studies have linked improvements in memory retention to a healthy diet, especially a sufficient intake of complex carbohydrate foods. One such study conducted at the University of Toronto compared a group of healthy seniors who ate a daily breakfast of a bowl of cereal, milk and a glass of white grape juice with a control group that only drank water for breakfast (The Franklin Institute Online 2004). Within 20 minutes of finishing breakfast, the cereal eaters scored 25% higher on memory recall and were able to remember more facts than the controls. It should be noted that the carbohydrates consumed in this study were complex in nature and thus able to sustain energy. Simple carbohydrates, on the other hand, are often low in nutrients and can actually upset the brain’s delicate energy balance by promoting short-term energy highs followed by extreme lows; this, in turn, often leads to lethargy and hunger.

In addition to supplying energy, dietary carbohydrate consumption has been shown to significantly impact mood and behavior via involvement in neurotransmitter action (Somer 1999). Suboptimal intake or a lack of carbohydrates in the diet can not only halt the brain’s main fuel supply but actually inhibit the creation of key neurotransmitters in the brain, potentially resulting in brain fog or mental confusion.

The Bottom Line: As a general guideline, most nutrition experts recommend that adults consume 45%–65% of their daily calories from complex carbohydrates to meet the brain’s unrelenting need for power.

Maintaining the Brain’s Transit System

While brain cells rely primarily on carbohydrates for energy, other tissues, enzymes and a variety of chemicals within the brain require protein for their structure and function. In fact, several key brain neurotransmitters depend on specific amino acids derived from protein-rich food sources in the diet. The balance of neurotransmitters in the brain plays an integral role in an individual’s mood, sleep patterns, cognition and overall brain performance. Many neurological diseases and mental brain disorders, such as Parkinson’s disease (PD), Alzheimer’s disease (AD) and attention-deficit disorder, are thought to be caused by imbalances in the brain’s neurotransmitters.

For example, individuals with PD typically exhibit characteristic symptoms of muscle rigidity and trembling hands, which can be attributed to the brain’s diminished ability to synthesize dopamine, the neurotransmitter associated with voluntary movement and fine motor coordination of the body. The amino acid needed for dopamine production is phenylalanine, found in foods such as almonds, eggs, meats and grains. Similarly, a lack of glutamate, the neurotransmitter associated with learning and memory, is thought to be linked to early memory malfunctions in AD, the most common form of dementia.

The Bottom Line: The good news is that it takes only two to three servings of quality protein intake each day to provide the nutritious mix of amino acids needed to help support healthy neurotransmitter function.

Chewing the Fat

Make no mistake about it: Growing and aging brains require the right amount of fat, which should come as no surprise considering that approximately two-thirds of the structural brain is made of fat (The Franklin Institute Online 2004). One way to improve your brain power is to consume the right dietary fats and oils to support cell membrane plasticity. Animal research has demonstrated a connection between the type and amount of fatty acid in the diet, the fatty composition of the brain cell membranes and the potential for positive impact on brain communication pathways (Yehuda et al. 1998).

In order for brain cells to function optimally, their membranes need to allow important molecules to cross through unimpeded. Therefore, the cell membranes need to be made up primarily of omega-3 fatty acids, not less healthy fats, like saturated fat, which tends to harden cell membranes.

The most abundant omega-3 fatty acid in the brain is docosahexaenoic acid (DHA), which constitutes a major component of the brain’s structural lipid membranes. DHA is an essential fatty acid and must be obtained through the diet. Including plentiful amounts of DHA in the diet has been shown to improve learning ability, whereas DHA deficiencies have been linked to learning deficits. Research has also linked low DHA levels in the brain to cognitive decline and incidences of AD. One study found that elderly people who ate fish once a week for 6 years developed 10% less cognitive decline than those who rarely or never ate fish; those who consumed fish two or more times weekly experienced a 13% reduction in cognitive decline (Morris et al. 2005a). Omega-3 fatty acids in general have also proved to be vital in promoting behavioral and cognitive functioning, including influencing emotional balance and positively affecting mood (Somer 1999).

The Bottom Line: Make it your goal to get at least two 6-ounce servings of fatty fish—such as salmon, light tuna, pollack or catfish—in your weekly meal plan. But limit your intake of fish or shellfish that have high mercury levels; for example, shark, swordfish, king mackerel and tilefish.

Follow Your Heart

According to an extensive report released by an expert panel of the National Institutes of Health (NIH), what’s good for the heart is also good for the head (Hendrie et al. 2006). Reducing heart-health risk factors may help maintain cognitive reserves while decreasing the risk for AD throughout the aging process. The brain relies on a vast network of blood vessels to ensure adequate nutrient, energy and oxygen delivery to its cells or neurons. Transporting the brain nutrients depends a great deal on the integrity of the cardiovascular system.

Maintaining healthy blood pressure and cholesterol levels is critical to heart and brain health; elevated cholesterol levels can contribute to clogged arteries in the brain. There is a great deal of scientific evidence linking diets high in saturated fats, cholesterol and trans fats to increased AD risk. In a recent Chicago Health and Aging Project trial involving more than 800 Chicago residents, researchers found that high intakes of saturated fat doubled the risk of getting AD, whereas moderate amounts of trans fats doubled or tripled the risk (Morris et al. 2003). Emerging research also suggests that high levels of cholesterol can result in brain cells being more prone to dementia.

Researchers have found an association between brain health and levels of vitamin B as well. A recent study showed a link between memory decline and AD in elderly individuals with suboptimal levels of B vitamins, specifically folic acid, vitamin B12 and B6, in individuals with AD (Kado et al. 2005). That’s why many health experts recommend taking a daily multivitamin supplement. “When it comes to brain health, taking a simple B-vitamin-complex supplement is well worth the effort of supplementing,” says R. Malcolm Stewart, MD, a Dallas-based neurologist and director of the American Parkinson Disease Association.

Maintaining a healthy weight as we age is just as important to the brain as it is to the heart. Excess weight is associated with vascular diseases, such as heart disease and stroke, cognitive problems and dementia. A recent study of 1,449 people in Finland concluded that a body mass index (BMI) greater than 30 (the definition of obesity) is associated with double the risk of dementia (Kivipelto et al. 2005). Midlife obesity, elevated cholesterol levels and increased systolic blood pressure are also linked to a much higher risk of dementia (Kivipelto et al. 2005), while elevated BMI has been associated with a higher risk of PD (Hu et al. 2006).

The Bottom Line: A heart-healthy diet and regular physical activity can promote weight loss and arterial health while decreasing the risk of cognitive decline.

Arm Your Brain With Antioxidants

Due to its high oxygen demands, the brain is particularly susceptible to oxidative stress, a process that is characterized by the production of free radicals and that leads to cellular dysfunction and ultimately cell death (Morris et al. 2002). Studies have shown that the effects of decades of free-radical attacks on areas of the brain may contribute to disease, diminished mental functioning, gradual memory loss and premature aging of the brain (Englehart et al. 2002). In the cases of PD and AD, damage from oxidative stress is believed to play a crucial role in the death of neurons and in the degenerative brain function that characterizes these diseases.

The best way to protect brain cells and membranes from oxidative stress and to reduce the number of damaging free radicals is to consume a diet rich in the antioxidants found in fruits and vegetables. Antioxidants have been shown to boost cognitive health and minimize disease risk. One study that tracked more than 1,500 Japanese-American men and women found that drinking fruit and vegetable juices at least three times a week may reduce the risk of AD by as much as 75% (Qi et al. 2006). The researchers in this study theorized that certain polyphenols—natural antioxidants found in fruits and vegetables—may have protected the participants’ brain cells from the type of plaque damage thought to cause AD.

Another study confirmed this antioxidant connection. Researchers at the Rush Institute for Healthy Aging, in Chicago, who followed 3,718 Chicago seniors (age 65 and over) found that eating 2.8 servings of vegetables per day helped slow the rate of mental decline by roughly 40% compared with eating only 0.9 of a serving per day (Morris et al. 2006). Green leafy vegetables, particularly spinach, seemed to produce the strongest benefits for study participants in retarding age-related central nervous system function and cognitive behavioral decline (Kang, Ascherio & Grodstein 2005).

Vitamin E is also important for brain health (Morris et al. 2005b). Two separate studies conducted in Chicago and Rotterdam reported that diets rich in vitamin E appear to significantly decrease the rate of mental decline and may help some people lower their risk for AD (Englehart et al. 2002; Foley & White 2002).

The Bottom Line: Most experts recommend getting antioxidants and vitamin E through diet, rather than through supplements. Consuming a varied diet provides the broadest range of complementary nutrients, phytochemicals and antioxidants to work synergistically in maximizing brain health. Therefore, the best place to assemble your antioxidant arsenal against cognitive decline is in the produce section, the frozen fruit and vegetable case and the whole-grain aisles of your local grocery store.

Food on the Brain

It is never too late to get started on boosting your brain-building nutrients and mental reserves for a lifetime of better health and mental well-being.

“The most proactive thing that [people] can do to keep their brain in shape is to think overall health,” says Conrad Earnest, PhD, lead researcher and director of the Exercise Testing Core at Pennington Biomedical Research Center in Baton Rouge, Louisiana. “Focus on eating for a healthy heart, supplementing with B vitamins, maintaining an ideal weight, staying physically fit, minimizing stress and challenging the mind.”


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About the Author

Melinda Safir, MS, RD, LD

Melinda Safir, MS, RD, LD IDEA Author/Presenter

Melinda Safir, MS, RD, LD, is a food and nutrition communications consultant in Dallas.