One of the main reasons behind these cravings and mood altering effects is increased serotonin synthesis. Serotonin is a neurotransmitter found predominantly in the brain, but is also found in other tissues; intestinal wall, blood vessels, and lung tissue. Its functions are diverse including appetite regulation, sleep/wake cycles, memory/learning, sexual behavior, temperature and pain regulation, muscle contraction, hormone regulation, cardiovascular function, and depression and mood.
Tryptophan, an essential amino acid (protein) found in foods like turkey, eggs and dairy, is the precursor to serotonin synthesis. Tryptophan crosses the blood-brain barrier entering into the brain where it is converted into 5-hydroxytryptophan (5-HTP) with the aid of an enzyme and vitamin B3 (niacin). 5-HTP is then converted into serotonin with the assistance of another enzyme and vitamin B6.
However, in order for tryptophan to cross the highly selective and protective blood-brain barrier, its blood concentration must be higher than other similar amino acids (tyrosine, phenylalanine, leucine, isoleucine, valine and methionine), and this is where carbohydrates come into play. Consuming high-glycemic carbohydrates results in high blood sugar and this stimulates the release of insulin from the pancreas gland. Insulin not only clears the blood of extra sugar, but it regulates the amino acid tissue uptake too – resulting in a higher tryptophan blood concentrations.
So, the intake of carbohydrates and especially sweets and simple sugars, increases insulin levels, which allows more tryptophan to enter into the brain where it can be used to make serotonin – the effects of which are mood altering. But, over consumption of high glycemic carbohydrates has negative consequences like reactive hypoglycemia, sugar cravings, increased body fatness (weight gain), insulin resistance, metabolic syndrome, diabetes, heart disease, and various cancers. So, how do you remedy this paradox?
To unravel this quagmire, I tell my patients to follow a well-balanced (not high carb and low-fat) diet consisting of low-glycemic carbohydrates, quality proteins and fats spread out throughout the day consisting of three main meals and two to three snacks – all balanced and based on their particular needs. Doing so will keep blood sugar and insulin levels within normal, and provide greater amounts of tryptophan available for serotonin synthesis, without the negative effects of consuming too many carbohydrates or high glycemic carbohydrates.
- On a side note, taking 5-HTP can circumvent tryptophan and insulin, and allow for greater production of serotonin, because 5-HTP does not require carbohydrate consumption. However, this natural supplement cannot be taken by those on antidepressant or selective serotonin uptake or MAO inhibitors. Check with your doctor before taking this supplement.
Of course, following a lifestyle program consisting of solid nutrition, supplementation and exercise is optimum for achieving overall good health and a much better outlook on life – good mood included.