WENDY ROSS
Our brain nerve cells or neurons communicate with each other by exchanging neurotransmitters. A relationship exists between three main monoamine neurotransmitters — serotonin, dopamine and norepinephrine and mental health and imbalances in these can lead to depression.
Monoamine oxidase is an enzyme that breaks these substances down, and if you have too much of this, then the levels of your neurotransmitters will drop.
Dietary inhibitors of monoamine oxidase include oregano, cinnamon, nutmeg, apples, berries, grapes, kale, onions and green tea. The natural monoamine oxidase enzyme inhibitors in fruits and vegetables may help explain why so many people report improved mood after switching to a whole food plant based diet.
Dysthymia, or ongoing low-level sadness, may not directly affect the ability to maintain a seemingly normal life, but it can certainly significantly affect a persons’ ability to achieve their full potential.
Constant mild anxiety or persistently low moods are often a sign that nutrition is less than optimum.
Abnormally low levels of neurotransmitters such as serotonin — the ‘happiness hormone” may be responsible for depression.
Serotonin regulates many important functions in the brain, including sleep, aggression, eating, sexual behaviour and mood.
We now have drugs such as SSRIs (selective serotonin reuptake inhibitors) that keep serotonin levels high. Unfortunately these medications have significant side effects for many people taking them. Some of these side effects are due to further depleting nutrients that were already missing from the persons’ diet.
A more natural approach is to use foods that have high amounts of these substances. Polyphenols are a large group of antioxidants found in plants and are a non-invasive, natural and inexpensive way to support a healthy brain. Serotonin cannot cross the blood brain barrier (that cleverly designed cell layer that stops toxic substances in our blood stream from affecting our brain).
Tryptophan is an amino acid and precursor of serotonin that is capable of crossing the blood brain barrier.
There are many amino acids that compete against each other for the transport systems that can carry them across this BBB.
Since tryptophan is present in animal protein in relatively small quantities it gets muscled out of the way in preference for other amino acids.
When we eat plant based foods, the carbohydrates they contain stimulate the release of insulin that causes our muscles to take up many of the other amino acids, leaving tryptophan first in line to get across the blood brain barrier into the brain. This was elegantly shown in a study at MIT.
Researchers there studied subjects who ate a turkey/egg & cheese sandwich compared to subjects who had waffles and OJ.
The latter, high carb group had tryptophan levels rise, while those in the turkey/egg/cheese group actually saw a drop in their tryptophan levels. So that thanksgiving turkey really isn’t much use in helping your mood.
Great food sources of polyphenols include apples, blackberry, dark chocolate, coffee, flaxseed meal, hazelnuts, green and black teas, hazelnuts, soy yogurt and red wine.
So eat your veggies, and finish off your meal with some fruit and a small serve of nuts or dark chocolate and enjoy!
Starting next week: Eight principles of food and health
Dr. Wendy Ross is the lead physician at the Penticton cancer clinic and The Herald’s new health columnist.