Topic

6.4 Nutritional Approach for Supporting Depression

Omega 3 Fatty Acids

The link between omega 3 fatty acids and brain health has been known for a very long time. That old wives tale that ‘fish is good for your brains’ came from somewhere and now we really are starting to see that this tale has validity. 

Your brain is 60% fat and the fats that it is composed of play a vital role in its normal healthy functioning. One of the most important types of fat in the brain are the omega 3 fatty acids. Omega 3 helps maintain membranes. The membranes of our neurons are vital to their performance. The membranes are composed of what is called a phospholipid bilayer, 2 layers of complex fatty structures that lay back to back. The healthy functioning of the membrane is essential for several reasons, all of which involve the movement of things across the membrane. As we have discussed earlier, signals move across neurons initially in the form of electrical impulses. This impulse happens in the form of charged particles moving to and fro across the membrane in a spinning, spiralling fashion. This electrical impulse reaches the very end of the neuron and can’t jump across the synaptic gap, so the signal has to stimulate the release of the relevant neurotransmitter to carry on the chain of events. The vesicle (a small sac filled with neurotransmitters) moves to the edge of the membrane, fuses with the membrane, then splits and releases the neurotransmitter into the synaptic gap. Our body’s ability to send signals throughout the nervous system is completely reliant upon a healthy membrane.

The fats that we eat will determine the state of our membranes, as they are the structural material our body uses to make membranes. The materials that are available are the materials that it uses. If we are consuming high amounts of trans fats and excessive saturated fats (not that saturated fats are bad, it’s all about ratios) and not enough of the omega 3 fatty acids then our membranes will be stiffer, less fluid, not very responsive and cell to cell communication will be greatly affected. On the other hand, with sufficient intake of the right fats, i.e. omega 3 fatty acids, our membranes will be more fluid and function better. As a result, the kind of communication mentioned will be much more efficient. Electrical impulses will flow faster, and neurotransmitters will be released more efficiently and at a higher level.

Omega 3 Helps Enhance Receptor Function

We have seen that a healthy membrane is absolutely vital for neurons to be able to carry their signals effectively and how fatty acids play a vital role in this. The next part of the picture, once the electrical impulse has travelled along the neuron and stimulated the release of the relevant neurotransmitter, is how the neighbouring neuron receives the signal in order to continue the flow of communication. This is where receptors come in. Receptors are specialised structures that are embedded in cell membranes. Their job is to identify specific compounds, and then bind to them. When the specific compound (technically referred to as a ligand) is identified, the receptor will bind to it. Once bound, (the receptor is built into the membrane and half of its structure is inside the cell) the compound will send signals to the inner working of the cell and instigate specific changes or chains of events. Omega 3 fatty acids can help receptors to function more effectively. This is partly due to the fact that they are helping the membrane work more effectively, allowing the receptor to successfully deliver its message. Omega 3 fatty acids also seem to improve receptor function across a broad spectrum of different receptors.

Omega 3 Reduces Inflammation

One final area where omega 3 fatty acids may offer benefit is their impact upon inflammation. There is a growing body of research that is showing an association between depression and pro-inflammatory compounds. One of the key roles of fatty acids in the body is their metabolism into end products called prostaglandins, which amongst other things regulate the inflammatory response. As discussed previously, there are 3 different types of prostaglandins. These are called series 1, series 2, and series 3. Series 1 is mildly anti-inflammatory, series 2 is powerfully pro-inflammatory and series 3 is powerfully anti-inflammatory, switching inflammation off.

Different dietary fatty acids are metabolised to produce different prostaglandins. Omega 3 fatty acids tend to be used in the production of anti-inflammatory prostaglandins. The omega 3 fatty acid EPA gets converted into the powerfully anti-inflammatory series 3 prostaglandin. So, the potentially anti-inflammatory action of omega 3 fatty acids may offer an additional therapeutic benefit.

What the Evidence Tells Us

We certainly have a good idea as to what omega 3 fatty acids do within the brain, and in theory, we could give biological plausibility to the reports that omega 3 fatty acids help manage low mood. What does the evidence say on this matter? Well, this is where things get very exciting, as the evidence on the role of omega 3 fatty acids role in depression is increasing.

There has been considerable epidemiological (the study of disease patterns amongst populations) data that shows a negative association between fish consumption and depression. This means, the higher the fish intake in the diet, the lower the incidence of depression. For example, a study of around 4000 Finnish nationals showed that the higher the fish consumption, the lower the risk of depression and suicidal tendencies. Combined data from the 1996/97 New Zealand Health Survey and 1997 Nutrition Survey, found that fish consumption was significantly associated with higher self-reported mental health status – i.e. the individual’s own personal perception of mood and outlook and depression scores.

Epidemiological data is interesting as it shows patterns of association. However, these associations may be related to many other factors and don’t necessarily prove cause and effect – i.e. that omega 3 was the beneficial factor. For this, we need experimental data such as the gold standard randomised double-blind placebo-controlled trials. Is there such evidence in support of omega 3? A Scottish study conducted by Peet and Horrobin took 70 patients who were suffering from persistent depression, despite receiving ongoing treatment. Participants were given either EPA or a placebo for 12 weeks. The group given EPA showed significant improvements compared to those in the placebo group in symptoms as listed in the Hamilton Depression Rating Scale, compared with those in the placebo group. A 2009 review of 3 individual studies – one on EPA in bipolar depression, one on major childhood depression, and one on unipolar adult depression also demonstrated some promising results. In the adult study, significant positive benefits were found by week 3 compared to placebo. The bipolar depression patients showed a 50% or greater reduction in Hamilton Depression Scale scores and the childhood depression participants in the treatment group displayed significant improvements in 3 individual rating scales. These references could easily go on and on, and we really encourage you to do some research to see just how broad and vast the evidence base is getting.

Tryptophan

Tryptophan is a nutrient that has certainly gathered quite a bit of attention in recent years, with headlines and articles abound. In many ways, this is totally understandable, because its role in our mental health is significant. Tryptophan is an essential amino acid. Essential meaning we cannot manufacture it ourselves like we can some other amino acids and we have to get it from our diet. Like all amino acids, it is a building block in the manufacture of proteins. Tryptophan is also the chemical precursor to the feel-good neurotransmitter serotonin, and consuming it can affect our mood. Tryptophan crosses our blood-brain barrier where it gets into the central nervous system. It goes through a sequence of transformation by enzymes, where it is converted into serotonin. However, there needs to be a little catalyst in order to essentially catapult tryptophan home into the CNS. That catalyst is a gentle insulin spike.

To maximise this we need to eat a rich source of tryptophan with a good quality complex carbohydrate. An example of this could be an oat bar made with banana, a tuna open sandwich or a turkey wrap. Something as simple as that can easily do the job. 

Vitamin B12 & Folate

Vitamin B12 is probably most widely regarded for its role in the manufacture of red blood cells. It does, however, have a critical role to play in mental health too. Firstly, B12 supports the functioning of myelin which, as we have seen is vital for communication between neurons. Even the slightest degradation or dysfunction of this can have a huge impact on mood. B12 is also vital in the process of methylation, which marks genes for expression. This assists in the production and metabolism of neurotransmitters, hormone production and other vital processes. B12 is also involved in the production of neurotransmitters called monoamines. These are involved in emotion, cognition and arousal.

Folate is another of the B vitamins that are associated with depression. There seems to be a link between folate and depression, and there is a chain of thought that low levels of folate lead to low levels of a substance called S-adenosylmethionine (SAMe), that is involved in neurotransmitter production and recycling. A 2005 review study found that both low folate and B12 levels were found in depressed people and that adequate levels of these two nutrients were associated with better responsiveness to drug treatments and better treatment outcomes.

Vitamin B6

When it comes to depression, vitamin B6 is up there on the ‘essentials’ list. As a nutrient, it has a vital role to play in the brain, with two main roles that are extremely pertinent to the pathophysiology of depression. Firstly, B6 is involved in the formation of myelin. Secondly, and probably most importantly B6 is vital for the conversion of tryptophan to serotonin. The importance of consuming foods rich in tryptophan was highlighted above. Once tryptophan crosses the blood-brain barrier it then needs to go through various steps of chemical conversion to become serotonin. B6 is involved in facilitating this.

Zinc

One nutrient that for some reason does not often get discussed in the mainstream press in terms of low mood and mental health, is the mineral zinc. This is a great disservice, as this seems to be one of the most critical nutrients in the whole picture. Many people associate zinc with immunity or for healthy hormones, however, zinc is actually highly concentrated in our brain. Especially high concentrations are found in a region of the hippocampus. One of zinc’s jobs is to maintain the blood-brain barrier, the protective barrier that allows the right things to enter the brain, and stops the wrong things from getting in. Zinc also modulates aspects of the stress response and seems to play a crucial role in neurological communication. Zinc is an essential cofactor for hundreds of enzymatic reactions. Like omega 3, zinc is another nutrient that has very encouraging evidence to support its use in low mood. Zinc deficiency has been found in several studies to induce depression and reduce focus and attention. A 2013 randomized, double-blind, placebo-controlled trial involved half of the participants receiving 25mg of zinc alongside antidepressant treatment, using SSRI drugs, and half receiving placebo alongside drugs. The results showed that those in the treatment group had significantly reduced scores in the Beck Depression Inventory in comparison to the placebo group. This important mineral should not be neglected at all.

Blood Sugar Balance

We have touched on this before so won’t go overboard with it again, but blood sugar management is of vital importance. Keeping blood sugar levels stable influences our mood. Whilst not immediately associated with depression, keeping your blood sugar even will make moods more stable which in turn influences your outlook and the way that you feel in general. The more stable and balanced you feel in terms of energy levels and general mood, the better you will feel within yourself. Depression can really affect the way in which you see the world and alter the filter through which you see and comprehend the world around you. There is less of a profound direct effect in comparison to the other nutritional elements mentioned, but it is of value none the less.

Nutritional Tips

  • Eat plenty of oily fish such as salmon, mackerel, herrings to get healthy helpings of preformed omega 3 fatty acids. We recommend at least 3-4 servings a week. More if you can manage it.
  • Eat turkey, tuna, bananas, eggs, spinach, and game meats to get plenty of the amino acid tryptophan. Make sure you eat them with a complex carbohydrate – so mashed banana on toast, open tuna sandwich, etc.
  • Eat plenty of green leafy vegetables, whole grains like brown rice, eggs, lean meats and fish to get a broad spectrum of B vitamins, especially B12, B6, and folate.
  • Eat prawns, shellfish and pumpkin seeds for a good quality source of zinc.