In today’s fast-paced “24/7” society, consumers often overlook foods and reach instead for drugs, as a quick way to improve alertness, slow the onset of cognitive decline or memory loss, or to modulate their mood. Bearing this out are the startling statistics on the market value of prescription drugs, such as antidepressants, sleep aids and alertness aids. According to Datamonitor, prescription antidepressants have global annual sales exceeding $15.6 billion, with U.S. sales accounting for more than 70% of this value. According to Packaged Facts, sales of OTC sleep aids are expected to approach $759 million by the year 2013. Some “alertness aids,” yet another drug type garnering attention from consumers, act as anti-sleep agents. One such product, modafinil--sold under the name Provigil®--was approved by the FDA to treat patients suffering from extreme sleepiness during the day, due to Parkinson’s and multiple sclerosis.
The military has also tested modafinil to see if it will enable GIs to go without sleep for two or three days at a time. Last year, Provigil had sales of $1 billion, accounting for nearly half of its manufacturer’s revenue.
“Let food be thy medicine and medicine be thy food.” This simple statement, made 2,500 years ago by the Greek physician Hippocrates, the “Father of Medicine,” embraces the preventative role that food plays in maintaining health. Fast forward to today, and research continues to draw a link between what people eat and their mood or state of mind. Some studies even suggest a poor diet may trigger aggressive behavior. As discussed below, emerging studies show certain foods and food ingredients, consumed as part of a balanced diet, offer a promising holistic and preventative approach toward brain and mental health. This article takes a look at an array of foods and food ingredients and their effect on two facets of brain health: (1) sharpening mental acumen, and (2) modulating mood or state of mind.
Cognition: Sharpening Mental Acumen
Several ingredients found to boost brain health by improving mental alertness or delaying the onset of memory loss include choline, phosphatidylserine and caffeine.
Choline has been recognized as an essential nutrient since 1998. This quarternary ammonium compound is classified with the B vitamins. Choline is associated with a growing list of biochemical functions, such as synthesis of 1) the neurotransmitter acetylcholine, which is linked to memory, and 2) phosphatidyl choline, a lipid required for synthesis of cell membranes. Choline is a major component of phosphatidyl choline, found in lecithin.
In 2001, the FDA recognized the importance of dietary choline by authorizing a nutrient content claim, with 550mg/day as the daily value.
Most people are choline deficient. Only 4% of adult females and 13% of adult males consume an adequate amount of choline, based on intake values recommended by the Institute of Medicine. An ironic explanation for the widespread deficiency could be that people are avoiding sources of choline, such as eggs and liver, because these foods are high in cholesterol. Other sources of choline are cabbage, cauliflower and soybeans.
Impaired memory and poor concentration are two effects of choline deficiency. A number of animal studies show that, when administered during neonatal development, choline can have a beneficial effect on memory. Studies on rodents reveal choline deficiency produces profound changes in brain structure and function, with one result being altered memory. In addition, offspring of rodents fed high levels of choline exhibited less age-related memory decline than controls.
In adult humans, choline may play a role in enhancing memory. Modest improvements on memory tests were noted in a double-blind study involving dementia patients treated with phosphatidyl choline for six months.
With its potential for improving cognition and the existing widespread need for increased consumption, choline presents an opportunity for new product development.
Phosphatidylserine, one of the phos-pholipids found in cell membranes, is the only ingredient with a qualified health claim concerning cognitive function. There are two claim options:
1) “Consumption of phosphatidylserine may reduce the risk of dementia in the elderly,” and
2) “Consumption of phosphatidylserine may reduce the risk of cognitive dysfunction in the elderly.” The claim is limited to dietary supplements containing soy-derived phosphatidylserine.
Caffeine was discovered in 1819. Caffeine and its cousins--theophylline (present in tea) and theobromine (present in chocolate)--are methyl xanthane alkaloids. A natural constituent of coffee, caffeine stimulates mental alertness and helps one focus on mentally tasking projects. Caffeine is present in colas, guarana and yerba mate, which are used in teas and some energy drinks. The caffeine content in coffee varies, depending upon the brewing method and the bean-roasting process. A cup of drip-made coffee contains about 100-175mg caffeine. Because high temperature destroys caffeine, dark roast coffee has less caffeine than lighter roasts. Carbonated cola soft drinks typically contain 10-50mg caffeine per 12oz. Energy drinks, such as Red Bull®, have about 80mg per serving. So, to sharpen mental alertness for that next job interview, reach for a cup of coffee.
Temperament: Attaining a Balanced State of Mind
Unbeknownst to many, diet plays a huge role in modulating mood and maintaining a balanced state of mind. The list of foods and food ingredients that help in this area include omega-3 fatty acids, chocolate, complex carbohydrates, green tea, theanine and gamma aminobutyric acid (GABA).
Omega-3 fatty acids are natural constituents of the human body and are recognized as ingredients that improve cognition, exert a beneficial effect on memory in Alzheimer’s patients and modulate mood.
The brain is composed of about 60% lipids (dry weight), with omega-3 fatty acids making up about 20% of nerve cell membranes and about 60% of the nerve cell membranes at the synapses where the cells connect. Two important omega-3 fatty acids are docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA)--metabolites of alpha-linolenic acid (ALA), an essential fatty acid. Because the metabolic conversion of ALA to these fatty acids is low, people need to obtain these fatty acids from dietary sources, such as fatty fish, like salmon, tuna, mackerel, rainbow trout, herring and sardines.
Omega-3s are important because they make brain cell membranes elastic, so electrical signals flow more readily from one cell to the next. Under one theory, DHA confers elasticity to channels within the membranes, allowing them to more readily change shape to facilitate the flow of the electrical signals. If the diet does not provide enough DHA, the brain will make do with the more rigid omega-6 fatty acids. The result is a less-flexible membrane that does not function as well. Also affected by the substitution are structures called G-proteins inside the cell membranes. Substitution with omega-6s reduces the ability of the G-proteins to help molecules on one side of the membrane communicate with molecules on the other side.
Until the early 1900s, diets were generally rich in omega-3 fatty acids. Since then, however, diets in Western countries have largely replaced omega-3 sources with foods rich in omega-6 fatty acids. Omega-6 fatty acids are found in oils from sunflower, corn, soy and palm--oils that are present in many fried carry-out foods, ready-to-eat meals and snack products. The shift in the dietary availability of omega-3s to omega-6s has been dramatic. According to Joseph R. Hibbeln, M.D., acting chief, Section on Nutritional Neurosciences at the National Institute of Alcohol Abuse and Alcoholism, about 20% of all calories in the U.S. diet come from soybean oil. This is up from less than 0.1% of all calories in 1909.
Growing evidence suggests that diets poor in omega-3 fatty acids may have disturbing effects on mood and behavior. In fact, low levels have been linked to increasing rates of major depression, aggressive behavior, suicide, homicide and violence.
Hibbeln has been actively engaged in championing the connection between omega-3s and depression. According to the World Health Organization, major depression is expected to be the second leading cause of disability worldwide by the year 2020. Research by Hibbeln found a high consumption of fish may be correlated with a lower prevalence of major depression across nine countries
Other studies link low omega-3 levels with aggression. Researchers have reported that habitually violent offenders had significantly lower blood concentrations of DHA than healthy controls
The suggested impact of omega-3s on mental health is another reason why food scientists should continue to find ways to incorporate these compounds into food and beverage products.
Feeling anxious? That might a good excuse to indulge in chocolate! Chocolate is produced from beans of the cacao tree, which are native to tropical South America. This sublime treat modulates mood on several fronts. First, its constituent tryptophan, an essential amino acid, plays a role in the production of serotonin, a mood-calming and anxiety-reducing neurotransmitter. Second, chocolate triggers the release of endorphins, natural opiates which make the body feel “balanced” and desensitized to pain.
Complex carbohydrates--compounds found in whole grains, legumes, pasta, fruits and vegetables, which also include ingredients such as maltodextrin and various starches--may also contribute to the production of serotonin. The precursor of serotonin, tryptophan, competes with other amino acids for transport into the brain, where conversion of tryptophan to serotonin takes place. Such competition impedes the transport of tryptophan across the blood-brain barrier. Studies, however, indicate that, when complex carbohydrates are consumed, insulin reduces the level in the blood of six or more of the competing amino acids, making the passage of tryptophan into the brain easier. Although other factors are at play, consumption of complex carbohydrates may provide a means for controlling stress.
Green tea originated in China around 2,700 B.C., and tea is the most widely consumed beverage, with more than 2 billion cups consumed worldwide every day. Consumption of green tea, prepared from leaves of the Camellia sinensis plant, has been shown to assert positive effects on mood, as well as cardiovascular disease, cancer, obesity and, potentially, dementia. The active components of the tea are catechins. These polyphenolic antioxidants comprise about 30% of the dry leaf weight, with epigallocatechin-3-gallate (EGCG) accounting for about 50% of the catechins.
In a recent study to evaluate the effect of EGCG on insulin sensitivity, researchers found that EGCG elevated mood in overweight subjects
Theanine, an amino acid found in green and black teas, has been found to promote a relaxed, but alert, mental state. When consumed at levels ranging from 50-200mg, theanine shifts the frequency of brain waves, measurable on the surface of the head, from their “normal” beta state of more than 14Hz (i.e., cycles per second) to a more relaxed alpha state of 8-13Hz. Clinical research links the alpha state to improvements in learning performance, mental acuity and concentration. Listening to certain musical passages can also induce the alpha state and research studies suggest this state facilitates learning of foreign languages.
The GABA molecule, synthesized from glutamic acid, is the key inhibitory neurotransmitter in the brain. Low levels of GABA have been associated with various mood disorders and insomnia. GABA is a popular food ingredient in Japan, where it is included in a wide range of products, including coffee, water, chocolate and candy. Recently, GABA attained self-affirmed GRAS status in the U.S. for use in beverages and beverage bases, candy, chewing gum, and ready-to-drink coffee and tea products.
As time unfolds, research continues to underscore the power of food as a key to health. In the future, we can expect more opportunities will be discovered for exploiting food as a holistic vehicle to promote brain health and modulate mood.pf
For more information, type “cognitive,” “mood,” “acuity,” “mental health,” “choline,” “phosphatidylserine,” “omega-3s,” “DHA,” “EGCG,” “ALA” or “caffeine” into the search engine at www.PreparedFoods.com.
References:
1 Hibbeln JR. 1998. Lancet. 18:1213.
2 Hibbeln JR. 2002. J Affect Disord. 69:15–29.
3 Virkkunen ME, et al. 1987. Biol Psychiatry. 22:1087-96.
4 Hibbeln JR, et al. 2006. Int Rev Psychiatry. 18:107-18.
5 Gesch CB, et al. 2002. Br J Psychiatry. 181:22-8.
6 Brown AL, et al. 2009. Br J Nutr.101:886-94.
