How can nutri­tion influ­ence brain functions?

First of all, the brain con­sumes con­sid­er­able amount of glu­cose. One of the ear­li­est sign of demen­tia is a decrease in the abil­ity of the brain to use glu­cose effi­ciently. As such a dys­func­tion is at the core of dia­betes, some neu­ro­sci­en­tists refer to Alzheimer’s Dis­ease as Type 3 diabetes.

The brain is also a fatty organ. Fats are present in the neu­rons’ mem­branes to keep them flex­i­ble. These fats are the omega 3 and omega 6 fatty acids mol­e­cules. Our brain is depen­dent on dietary fat intake to get enough fatty acids. Omega-3 fatty acids can be found in cold-water fish (such as mack­erel, her­ring, salmon, and tuna), kiwi, and wal­nuts. Docosa­hexaenoic acid, or DHA, is the most abun­dant omega-3 fatty acid in cell mem­branes in the brain.

In gen­eral, the brain is highly sus­cep­ti­ble to oxida­tive dam­age. This is why antiox­i­dant food has become pop­u­lar for their pos­i­tive effects on brain func­tion. Antiox­i­dants are found in a vari­ety of food: Alpha lipoic is found in spinach, broc­coli and pota­toes; Vit­a­min E is found in veg­etable oils, nuts, green leafy veg­eta­bles; Vit­a­min C is found in cit­rus fruit and sev­eral plants and veg­eta­bles. Berries are well known for their antiox­i­dant capac­ity but it is not clear which of their many com­po­nents has an effect on cognition.

Based on these obser­va­tions, Dr. Larry McCleary (whose inter­view you will find at the end of this Chap­ter) rec­om­mend a diet con­tain­ing fatty fish, veg­eta­bles and sal­ads, non-starchy fruits (like berries) — that are high in free rad­i­cal fight­ing com­pounds — and nuts.

As most peo­ple you prob­a­bly have bought or thought of buy­ing nutri­tion com­ple­ments. Indeed it is hard to get all the good nutri­ents in one’s diet. The most com­mon con­sumer pur­chase is herbal and vit­a­min sup­ple­ments pur­ported to improve mem­ory. Table 2 shows you the most recent find­ings asso­ci­ated with well-known sup­ple­ments such as Ginkgo biloba.

How­ever one has to be cau­tious. One neg­a­tive aspect of self-medication with herbal sup­ple­ments is the fact that some prod­ucts have been shown to coun­ter­act the effects of pre­scrip­tion and over-the-counter med­ica­tions. For exam­ple, in 2001, Dr. Piscitelli from the National Insti­tute of Health (NIH) showed a sig­nif­i­cant drug inter­ac­tion between St. John’s wort (hyper­icum per­fo­ra­tum), an herbal prod­uct sold as a dietary sup­ple­ment, and Indi­navir, a pro­tease inhibitor used to treat HIV infec­tion. The herb has also caused neg­a­tive inter­ac­tions with can­cer chemother­a­peu­tic drugs and with birth con­trol drugs.

Experts usu­ally rec­om­mend a bal­anced diet, that is get­ting healthy nutri­ents (Omega-3, antiox­i­dants, etc.) from the food you eat, rather than ingest­ing sup­ple­ments. Few stud­ies so far have shown that sup­ple­ments are ben­e­fi­cial to brain health. More impor­tantly the best dosage of these sup­ple­ments is not know.

Table 2. Sum­mary of recent find­ings on sup­pos­edly brain-enhancing dietary supplements.

Keep learn­ing by read­ing more arti­cles in the Resources sec­tion, and also please con­sider join­ing our free monthly Brain Fit­ness eNewsletter

This new online resource is based on the con­tent from the book The Sharp­Brains Guide to Brain Fit­ness (May 2009, $19.95), by Alvaro Fer­nan­dez and Dr. Elkhonon Goldberg.