Food, Mood, the Brain and Beyond
“We used to think our future was in the stars. Now we know it’s in our genes”
James Watson Nobel laureate and co-discoverer of DNA
There is growing evidence that eating the correct diet may help prevent many disorders of the mind such as epilepsy, schizophrenia, dementia and autism but just how powerful is our diet compared to our genetic constitution? Viewed another way, maybe we should be considering the combined power of our genetic make up and diet since genes for certain disorders may only express themselves in special situations. For example, I think many psychiatrists agree that certain people have addictive personalities. In the presence of excess alcohol the gene expresses itself and the person becomes an alcoholic. What is interesting is the fact that most reformed alcoholics often turn to another addiction such as smoking or eating to fill the gap in their lives. Those who win through and turn their backs on destructive addictions may find themselves following strict religious or work-based pursuits. Just as humans can become addicted to alcohol so to can they become addicted to drugs. There is a growing body of evidence that suggests our genetics are at the root of these evils.
Studies of brains from alcohol addicts show that they have fewer dopamine receptors than non-alcoholics; maybe this was genetically determined. Genes have also been implicated in smokers. In one study of 283 smokers over one third had an unusual gene that was not present in non-smokers. The gene, named D-2, was also found to be responsible for the low number of dopamine receptors discovered in the brains of alcoholics. Now we can start to see a strong genetic link developing between the two addictive personalities. With one gene defect we can see two very different addictive behaviours and potential life style and health outcomes. Our addicts may be viewed as “medicating” themselves since both alcohol and smoking will elevate the dopamine levels (by blocking its re-uptake) and stimulate the pleasure centres deep within the brain. So to will certain foods such as carbohydrates since the release of another happy hormone, serotonin occurs.
When it comes to a discussion on diet and health the human brain must feel a bit left out. We are all aware that certain foods and vitamins feed our skin, a low animal fat diet is good for the heart, drinking plenty of water helps our kidneys and our bones benefit from extra calcium whilst the joints often feel better for a oiling up with a daily dose of cod liver oil. What about our brains – they have very special needs but how many of us give this amazing structure a second thought?
Compared to the lightweight brain our closest ancestors, the monkeys, which weigh about 105 grams the average human brain weighs in at a colossal 1350 grams. From a developmental point of view it is the first tissue to develop, at about 16 days after conception. Eating well is vital if you are trying to conceive since you may not be aware that you are pregnant by the time your babies brain has started to develop!
Even though the adult brain forms only 2% of our body weight it receives over 15% of the blood pumped from the heart and consumes well over 20% of the total body oxygen and glucose used each day. Such a high blood supply and fuel consumption shows how essential fresh supplies of brain food are for healthy brain function. However, don’t forget that the feeding of a healthy brain starts before birth!
It has been said that the seeds of good adult health are sown before conception, during pregnancy and during infancy. The seeds of health being the specific nutrients contained in our daily diet. It has been recently been discovered that certain oils (belonging to the fat family known as “omega-3’s”) are essential for the normal development of the brain and nervous system during pregnancy. This reliance on the omega-3 fats continues for the first couple of years of life. One specific member of this fat family known as docosahexaenoic acid or DHA for short, has the ability to stimulate the growth of the retina (the light sensitive inner part of the eye) and the brain itself. DHA can, therefore, be considered to be a specific brain nutrient. Apart from the brain DHA plays an important function in the correct functioning of the immune system.
The developing baby is reliant on it’s mother for an adequate DHA supply. Dietary intake accounts for the majority of DHA used by the baby and obtained through the placenta and later on in the breast milk. Many formula milk are very low in DHA. In fact the fat content of most formula feeds are based in commercially processed oils which contain high levels of potentially damaging fats known as “trans fatty acids”. It has been estimated that breast milk contains over 30% more DHA than formula feeds; breast is always best!
Just take a trip around any supermarket and you will be confronted with an enormous and ever-growing variety of low-fat or fat-free food products. These foods are being aimed at our obsession with low fat diets promoted by the media. With our ever growing knowledge about the importance of essential fatty acids it is questionable if this new style of eating is the healthy option it is made out to be. However, this is not an invitation to throw caution to the wind and pig out fatty foods. I would still advise moderation in animal (saturated) fats while increasing oily fish, and foods high in monounsaturated fats – the good fats!
The shift in modern eating habits is causing serious concerns regarding the growing followers of the low-fat culture. This diet trend is causing a drop in the essential fatty acid intake in the general population. Most worrying is the potential adverse effects this may have on mothers to be and their babies developing nervous system.
Recently, an item of news announced the fact that the brains of pregnant women shrank over the cause of their pregnancy. The study was carried out at the Royal Postgraduate Medical School. The scientists were investigating the causes of pregnancy related blood pressure problems when they stumbled across the unexpected finding showing that the brains of the women they were studying were shrinking. The investigating team discovered that the mothers were deficient in essential fatty acids that were needed by the developing babies brain and nervous system. Such was the demand that the stores contained in the mothers brain were mobilised into the general circulation for delivery to the developing baby. The adult brain is a rich reserve pool of these special fats. Happily, however, the brains returned to normal after 6 – 10 months but the fact remains that the reserve pool was tapped into demonstrating the absolute necessity for these fatty acids.
It is common knowledge that folic acid is essential for the healthy formation of the nervous system. Most pregnant mothers are now given tablets of 400 mcg folic acid to prevent spina bifida, but what about oil supplements?
Deficiencies of the omega 3 family can lead to learning difficulties because of their importance in the development of the nervous system but because learning and behavioural problems are only normally noticed some years after birth and are not life threatening, unlike spina bifida, it has not prompted much attention. There is a popular misconception that fats act as nothing more than storage systems for energy or as packing material. Only recently has it become acknowledged that fats have a very significant role in the metabolism and development of the body. There is a clear need for a greater understanding of the role of fatty acid metabolism in the maintenance of cell membrane health. There is evidence accumulating that any dietary programme aimed at helping an autistic child should involve a balance of both omega 3 and 6 fatty acids rather than gross overloading of one form . Evening Primrose Oil consists largely of Gamma Linolenic Acid, an Omega 6 acid. There are other, richer sources of Gamma Linolenic Acid, such as Borage (Star Flower) Oil but it is claimed that this is less well tolerated than the oil from Evening Primrose. Fish oils such as Cod liver oil have the added advantage of including supplementary Vitamin A, which is likely to be, is short supply in people with autism.
Flax seed oil is a rich source of Omega 3 acids. A daily dose of flaxseed oil will re-balance the situation. Taken at a dose of 1 – 2 grams a day it will provide all the necessary fatty acids needed for health. Flaxseed oil is a richer supply of omega 3’s than fish oil, almost twice as concentrated in fact. From the high content of linolenic acid contained in flax oil the body can make all the DHA it needs.
The adult brain is not a static structure. Our ideas about the brain have changed since the early days of neurology and its plasticity (the ability to change and adapt to different situations) has now been appreciated.
The chemical environment of the brain is all important. Even minor nutritional deficiencies can major implications on healthy brain function. It has been noted that symptoms of dementia can occur long before the levels of vitamin B12 and folic acid are shown to be low in blood tests. The findings of vitamin B12 deficiency is not uncommon in Alzheimer’s disease further supporting the importance for a good nutritional balance. Unfortunately by the time symptoms start to be noticed supplementation may come too late. A long term minor deficiency has been suggested to cause slow and irreversible changes in the nervous tissue that is unresponsive to corrective supplementation.
As with many nutritional substances there is a good deal of interaction between the food chemicals that enter the brain. Vitamin C, for example, plays an essential part in the healthy actions of another important brain food, the amino acid known as phenylalanine. Phenylalanine works to produce nerve transmitting substances (called neurotransmitters) which regulate the electrical activity of the brain.
Neurotransmitters are responsible for an elevated and positive mood, alertness and mental well being, a lack causes many brain disorders such as depression and schizophrenia.
As well as vitamin C the mineral zinc has a part to play in mental health. It has been noticed that many people suffering from irritability, nervousness and anxiety have higher than normal levels of copper circulating in their bodies. Copper and zinc have an interesting relationship in that a deficiency of zinc causes an excess of copper to accumulate. Supplementing your diet with zinc can help re-balance the situation but care must be taken to avoid taking too much zinc which will cause a copper deficiency! It is best to take professional advice before taking large doses of zinc but a 15mg daily dose is considered quite safe for general uses.
Zinc has been studied in great detail and a team at the University of Michigan has shown a significant relationship between high academic grades and high zinc levels. Zinc deficiency is prevalent in our society mainly because of poor soil quality, food processing and bad cooking techniques.
Just like a fire an epileptic fit starts with a single spark, but the spark in this case is an abnormal brain impulse. The neurotransmitter known as gamma-aminobutyrate acid or GABA for short plays a key role in controlling brain impulses. GABA is the most prevalent transmitter substance in the brain and has many functions, the most important of which is a calming effect over the nervous system.
The brain of epileptics, hyperactive children, insomniacs, cerebral palsy sufferers, hypertensives, anxiety sufferers and those with learning problems, anti-social behaviour and mental retardation all benefit from elevating the GABA levels. GABA has no serious side effects even in doses of up to 40 grams (the normal dose ranges from 250 mcg – 1,000 mcg daily).
It is interesting to note that zinc again makes an appearance in the natural treatment of epilepsy. Zinc is needed for the production of GABA, along with another amino acid called glutamic acid. Numerous experiments have shown that a zinc deficient diet aggravates epilepsy and causes more frequent fits and seizures.
So far it can be seen that we need adequate zinc, glutamic acid and vitamin C for the correct balanced production of neurotransmitters but the list does not stop there. Vitamin B6 acts as a special co-factor and helps convert the glutamic acid into GABA. If this vitamin is low in the diet, despite of adequate amounts of zinc, vitamin C and glutamic acid, the reactions will not occur and GABA levels will fall.
The major structural fats found in the brain are called phospholipids. One particular phospholipid known as phosphatidylserine appears to be important in the control of mood and mood related problems. Normally this substance is produced naturally in the brain but in individuals who have deficiencies of vitamin B12, folic acid and other essential fatty acids the production of phosphatidylserine is dramatically reduced. Low levels are often found in the brains of elderly subjects but it’s concentration in younger people may be directly related to depressive mood states.
The primary use of phosphatidylserine in nutritional medicine is in the treatment of depression and impaired mental function in the elderly. Very good results have been obtained in a number of studies. Supplementing the diet with phosphatidylserine appears to improve neurotransmitter release (especially acetylcholine), memory and age related changes.
How phosphatidylserine aids in the treatment of depression is unknown. It does not affect serotonin levels like classic antidepressants nor does it interfere with other neurotransmitters. Phosphatidylserine does, however, improve the quality of brain cell membranes and helps control the levels of cortisol, a hormone released from the adrenal glands which has been found to be elevated in depressed subjects.
All in all, there is much evidence to suggest that the brain needs specific nutrients and it responds very well to corrective supplements. Feeding your brain well will make sure that it functions optimally and guarantees that long term deficiency symptoms do not occur. Such symptoms are so slow in developing that they are often written off as being age related changes for which nothing can be done. This is just not satisfactory when prevention is so easily achieved by a knowledge of what to feed your brain with.