Nutrition and Mental Health

Always contact your GP if you are planning a new diet or exercise regime.

Please note that this is not a diet book. The following is for educational purposes only.

Taking antidepressants alone won’t cure Depression or Anxiety if our Nutrition and blood sugar have more ups and downs than a ship on a stormy sea, Since many antidepressants (SSRIs*) work by increasing serotonin levels in the brain (78.) A person with too high blood sugar is already getting too much Serotonin taking SSRIs is only going to make the problem worse and a person with Low Blood Sugar levels isn’t producing enough then SSRIs is probably going to help but it does not solve the underlying problem (59.)

(*Selective serotonin reuptake inhibitors)

As already stated Anxiety and depression are very complex topics and Blood Sugar and Neurotransmitters levels are not the only cause As we’ll discuss in part 3, However, a healthy blood sugar system will ensure the transport of the right levels of precursors for both serotonin and dopamine into the brain (59) at least giving us a fighting chance.

People generally never think of the links between depression and other mental health issues with nutrition, Depression is more typically thought of as strictly biochemical-based or emotionally-rooted (80.)

Blood Sugar Imbalances have also been linked to several other diseases. A recent meta-analysis found significant positive associations between higher Glycemic index and higher incidence of diabetes, coronary heart disease, gallbladder disease, breast cancer, and all diseases combined (79.)

The dietary intake pattern of the general population in many western countries reflects that they are often deficient in many nutrients, especially essential vitamins, minerals, and omega-3 fatty acids (81.) When we take a close look at the diet of depressed people, an interesting observation is that their nutrition is far from adequate. They make poor food choices and select foods that might actually contribute to depression(80) As shown in reference points (359 & 360) people generally consume higher sugar diets which can lead to depression, rather than having depression then consuming higher sugar.

Studies have shown traditional diets like the Mediterranean diet and the Traditional Japanese diet give you 25-35% less chance of having depression compared with The Traditional Western Diet (361.) The traditional Japanese and Mediterranean diets tend to be high in vegetables, fruits, unprocessed grains, and fish and seafood, and to contain only modest amounts of lean meats and dairy. They are also void of processed and refined foods and sugars, which are staples of the “Western” dietary pattern (361.)

On January 30, 2017, the journal BMC Medicine published a study by Felice Jacka PhD ‘A randomised controlled trial of dietary improvement for adults with major depression’ (82.)

Professor Jacka’s team recruited 67 men and women with moderate to severe depression who reported eating a relatively unhealthy diet. Most were taking antidepressants and/or were in regular psychotherapy. Half of the people were put on a modified Mediterranean diet (Mod Med Diet) and required them to attend dietary support sessions with a nutritionist. The other half continued eating their usual unhealthy diet but were required to attend social support “befriending” sessions.

After 12 weeks, people in the ModiMed diet group saw their scores improve on average Thirty-two per cent. People in the unhealthy diet group improved by only about 8% (82,83).


Carbs aren’t good or bad, it’s just that in the traditional western diet we over-consume too many refined carbs and sugary snacks/drinks, causing blood sugar spikes. Studies have also shown that consumption of diets low in carbohydrate tends to precipitate depression (80) Remember the brain needs the goldilocks effect of Glucose, Not too much, not too little.

In the above study Carbs were approx 37% of the daily intake and those carbohydrates consisted of fruits and vegetables and whole grains. These are more likely to provide a moderate but lasting effect on brain chemistry, mood, and energy level than the high GI foods (80, 82.) Foods that were discouraged were primarily sweets (80,82.) If you do eat high-carb foods make sure you don’t eat them without some fibre, fat, or protein. These will slow down the rate at which the glucose is absorbed into the bloodstream.

Do not eat sweets or starchy foods before bed. This is one of the worst things the hypoglycemic person can do. Your blood sugar will crash during the night, long before your next meal is due. Chances are your adrenals will kick into action, creating restless sleep or that 3 a.m. wake up with anxiety (59)


Evidence suggests that adequate intake of protein may be required in the maintenance of mental health (77.) Proteins are made up of amino acids and are important building blocks of life. As many as 12 amino acids are manufactured in the body itself and remaining 8 (essential amino acids) have to be supplied through diet. A high-quality protein diet contains all essential amino acids. Protein intake and in turn the individual amino acids can affect the brain functioning and mental health (80.)

In the study (82.) Fried food, fast food, processed meat were also discouraged meaning try and get your protein sources from a variety of lean red meat, chicken, fish, eggs and plant based proteins.

Many of the neurotransmitters in the brain are made from amino acids. The neurotransmitter dopamine is made from the amino acid tyrosine and the neurotransmitter serotonin is made from the tryptophan we discussed earlier the effects they can have if we get too much or too little of these produced in the brain.

Dietary Fat (Omega 3)

Dietary fat may also play a role in mental health. The dry weight of the brain is 60 per cent fat (88) and low levels of omega-3 fats and cholesterol are significant risk factors for major depression and suicide (89). Omega-3 fats, which cannot be produced by the body and must be obtained from the diet (77).

Research findings point out that an imbalance in the ratio of the EFAs, namely the omega-6 and omega-3 fatty acids, and/or a deficiency in omega-3 fatty acids, may be responsible for the heightened depressive symptoms associated with low plasma cholesterol (77.)

Studies have shown that Omega 3 Fatty acid, especially DHA, may decrease the development of depression (84,85) and an inverse relationship between dietary omega-3 fatty acids and anxiety disorders has been demonstrated (86). Preliminary evidence suggests that omega-3 supplementation may be beneficial in the treatment of anxiety (87).

Overall a diet that is lower in high starchy carbohydrates in favour of Vegetables, fruits, protein and healthy fats should help lower blood sugar. Everybody is unique and has individual needs, Speak to a professional health and fitness adviser to work out yours.

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