Food and Mood
by Paul Jaconello, M.D.
Doctor Jaconello is the Medical Director of the Jaconello Health Centre for Nutritional and Preventive Medicine
Presently, public opinion about eating habits is changing to diets higher in protein, higher in fats and lower in carbohydrates. Dr. Atkinís high protein, low carbohydrate diet has gained ground, and many people in their endeavour to loose weight are embarking on this kind of diet. Carbohydrates are now the bad guys to many and protein is king.
Also, the concept of calorie restriction in prolonging life and reducing risk to cancer, diabetes and heart disease is becoming more known to the public.
On top of this, there are certain conditions where it appears that consuming carbohydrates can actually be effective in not only reducing weight but in improving mood.
Food constituents can affect brain biochemistry. The most researched areas where consumption of carbohydrates has a beneficial effect on mood and weight control include seasonal affective disorder (SAD), premenstrual syndrome (PMS) and carbohydrate craving obesity (CCO).
In these conditions, individuals when they consume carbohydrates feel more energetic, their mood improves and their minds become clear. Their carbohydrate cravings are usually accompanied by additional calories coming from fats so causing an inordinate rise in calorie intake and consequent weight gain.
Seasonal depression is characterized by weight gain, depression and carbohydrate cravings beginning in the fall and ending in spring when the above symptoms decline ant the weight is lost, the depression lifts and with it the need for carbohydrate/fat snacks.
In certain forms of premenstrual syndrome, there are all of the above symptoms occurring in the post-ovulation phase of the menstrual cycle and declining in the period between menstruation and ovulation.
In CCO, characteristically those suffering from this condition have their carbohydrate cravings in the afternoon and evening. They feel better, are less depressed and more energetic when they do this so they snack large amounts of extra calories to gain this wellbeing.
So what do carbohydrates do to the brain? They increase brain serotonin levels. Serotonin is a neurotransmitter which suppresses appetite and improves mood when its levels are low. However, when brain serotonin levels are normal or already high, more serotonin will produce a state of excessive sleepiness, fatigue and less efficiency. This is probably one of the reasons why those who are not carbohydrate cravers tend to fall asleep and make more mistakes at work after eating a carbohydrate rich lunch. How this occurs is that the ingestion of sugars and simple carbohydrates will initiate a raise in insulin levels.
Insulin is a hormone that regulates blood sugar levels and facilitates the uptake of glucose into muscle tissue and certain amino acids such as tyrosine, phenlyalanine and the branched chain amino acids (leucine, isoleucine and valine) but not tryptophane. Tryptophane is the amino acid precursor to serotonin. It is actively transported across the blood brain barrier into the brain where it is converted to serotonin by an enzyme called tryptophan hydroxylase. The other amino acids compete with trptophan at the blood brain barrier (BBB). Since the levels of other amino acids drop after an insulin surge, tryptophan has less competition and can more effectively cross the BBB and get into the brain and thus increase serotonin levels and activity, thereby effecting mood.
Tryptophane hydroxylase has a relatively low level of affinity to its substrate tryptophan and therefore by increasing the level of substrate, more is available, the enzyme will work faster and the conversion to serotonin will be expedited.
Eating a high protein snack or meal does not increase brain serotonin levels as tryptophan does not get access to the brain because of the presence of the other amino acids which compete for the transport sites. That is why individuals who go on high protein, low carbohydrate diets who have SAD, PMS and CCO can become quite ill since their brain levels of serotonin are already low and the high protein diet will accentuate the deficiency of serotonin!
It is in these conditions that the use of pure carbohydrate snacks given between meals and at night will actually suppress appetite, improve energy, elevate mood and improve productivity.
Nutritious snacks such as sweet potatoes, potatoes, parsnips, turnips, oatmeal and honey and glucose drinks that actual stimulate insulin production can have profound beneficial effects on the true carbohydrate craver and in the health problems associated with serotonin deficiency which are SAD, PMS and CCO.
This strategy will not work when the carbohydrate craving is absent and actually will tend to make individuals worse with increased fatigue, low energy, sleepiness and reduced emotional tone levels.
In summary, it seems what you eat can effect your mood and wellbeing and that what diet is good for one is not good for another.
Paul Jaconello, M.D.
The concepts in this article were culled from a lecture given by Richard Wurtman, M.D., Director of MITís National Sponsored Clinical Research Centre, given in May 2002 at The Ninth International Symposium of Functional Medicine.
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