DEPRESSION

The statistics for depression in the UK are… well… a depressing read. The current estimate is that one in five adults in the UK will be affected by depression at some point, with the highest number being in the 50–54 age group. Out of these, more are women. It is a condition that – frighteningly – is beginning to affect younger people, too, with 19 per cent of the over-16s in this country having reported depression to their GP. Certain demographics do appear to be at greater risk than others. A sizeable 27 per cent of people who are divorced or separated show signs of the condition, compared to 16 per cent of those that are married. Other groups such as those on a low income or the unemployed also show greater patterns of depression. The thing is, depression can be a really tricky condition, as the feelings that we can get are a normal (if occasional) part of the human experience, so often, in the early stages at least, it is difficult for the sufferer and those around them to determine normal highs and lows from depression of a more serious nature.

So, what is depression in the clinical sense? The symptoms can vary from individual to individual but common features of depression are a lasting feeling of sadness and hopelessness. There may also be a loss of interest in the things that you would usually enjoy doing, from hobbies through to social situations and interpersonal pleasures. Tearfulness can also be a frequent problem. The symptoms aren’t purely mental, either; depression very often has strong physical symptoms associated with it. Severe fatigue, disturbed sleep, appetite loss or extreme appetite increase, aches and pains are all associated with depression. These symptoms can manifest themselves in many combinations from individual to individual. In its less serious incarnation, depression may leave the sufferer feeling just a little down and demotivated with life. However, when things get serious, this condition really can of being suicidal and feelings of immense hopelessness. Certain neurological conditions such as Parkinson’s disease affect specific regions of the brain. Depression seems to affect multiple regions such as the prefrontal cortex, hippocampus, amygdala and thalamus. We are still in the very early days when it comes to determining the precise pathophysiology of depression, but one thing that is clear is that there is a series of abnormalities in the production of transmitters and their ability to instigate their relevant responses.

NUTRITIONAL APPROACH FOR MANAGING DEPRESSION

OMEGA 3 FATTY ACIDS

The link between omega 3 fatty acids and brain health has been known for a very long time. That age-old wive’s tale that ‘fish is good for your brains’ came from somewhere and now we really are starting to see that this tale has validity. I’m sorry to break this to you, but you are a fat head! Your brain is 60 per cent fat and the fats of which it is composed 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, two 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. Then, as we know, the membrane in a spinning, spiralling fashion. Then, as we know, 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. This consists of the vesicle, the small sac filled with neurotransmitters, moving to the edge of the membrane, fusing with the membrane, then splitting and releasing the neurotransmitter into the synaptic gap. Both of these aspects of sending signals throughout the nervous system are absolutely, completely reliant upon a healthy membrane. The fats that we eat will determine the state of our membranes, as they are the structural material that our body uses to make membranes.

But, obviously, the materials that the body has available are the materials that it uses to build membranes. 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 and not very responsive, while communication across them will be greatly affected. On the other hand, with sufficient intake of the right fats, such as omega 3 fatty acids, our membranes will be far more fluid and function much better and, as a result, the kinds 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

So 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, then stimulated the release of the relevant neurotransmitter, is how the neighbouring neuron receives this signal in order to continue the flow of communication. This is where receptors come in. Receptors Their job is to identify specific compounds, then bind to them. When a compound (technically a ‘ligand’) is identified, the receptor will bind to it. When it binds to it, as the receptor is built into the membrane and half of it is inside the cell, it will send signals to the inner cell and instigate specific changes or chains of events. Omega 3 fatty acids can help receptors function more effectively, partially because they help the membrane to work better, which does have a bearing on the extent to which a receptor can 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 showing an association between depression and pro-inflammatory compounds. One of the key roles of fatty acids in the body is their metabolism into prostaglandins which, among other things, regulate the inflammatory response. There are three different types of prostaglandin. These are called Series 1, Series 2 and Series 3. Series 1 is mildly anti-inflammatory; Series 2 is powerfully pro-inflammatory; while Series 3 is powerfully anti-inflammatory. Different dietary fatty acids are metabolised to produce different prostaglandins. Omega 3 fatty acids tend to metabolise into anti-inflammatory prostaglandins. The omega 3 fatty acid EPA gets converted into powerfully anti-inflammatory Series 3 prostaglandin. So, the potentially anti-inflammatory action of omega 3 fatty acids may offer an extra benefit.

WHAT THE EVIDENCE TELLS US

We have a good idea as to what omega 3 fatty acids do within the brain, so in theory we could give biological plausibility to the reports that omega 3 fatty acids help symptoms of depression. But what does the evidence say? Well, this is where things get exciting.

There has been considerable epidemiological (the study of disease patterns among populations) data that shows a negative association between fish consumption and depression. A negative association basically means, in this case: the higher the fish intake, the lower the incidence of depression. For example, a study of around 4,000 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 (an individual’s personal perception of their mood, outlook and depression scores) .

Epidemiological data is interesting, as it shows patterns of association. However, these associations may be related to many other factors, so don’t necessarily prove cause and effect (for example, 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… oh, yes there is! A Scottish study conducted by Peet and Horrobin in 2002 took 70 patients who were suffering with persistent depression, despite receiving ongoing treatment. Participants were given either EPA or a placebo for 12 weeks. The group given EPA at a dosage range of 1g per day had significant improvements in the Hamilton Depression Rating Scale compared with those in the placebo group . A 2009 review of three 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 three compared to placebo. The bipolar depression patients showed a 50 per cent or greater reduction in Hamilton Depression Scale scores and the childhood depression participants displayed significant improvements in three rating scales in the treatment group . These references could easily go on and on and I really encourage you to do some research and some digging to see just how broad and vast the evidence base is getting.

TRYPTOPHAN

Tryptophan has had quite a bit of press attention in recent years and its role in our mental health is significant. Tryptophan is an essential amino acid; we cannot make it ourselves, we have to get it from our diet. Like all amino acids, it is a building block in the manufacture of proteins, but it has another trick up its sleeve. Tryptophan is 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 (CNS). It goes through a sequence of transformation by enzymes, where it is converted into serotonin. However, there needs to be a catalyst to catapult tryptophan home into the CNS. That catalyst is a gentle insulin spike.

Long story short, to maximise this we need to eat a rich source of tryptophan with good-quality complex carbohydrate. An example could be an oat bar made with banana, a tuna open sandwich, or a turkey wrap. Something as simple as that. There are a lot of studies around that show positive results using tryptophan supplements, but these are not available in the UK. We have something called 5HTP (5-hydroxy tryptophan), a partially metabolised version of tryptophan, which can be highly effective. However, please note, from clinical experience I can tell you that this stuff is powerful! Please don’t just take it willy-nilly. Work with a qualified practitioner who can ensure that you use this safely as well as effectively.

B VITAMINS

The B vitamins are one of the most important groups of nutrients and have numerous roles to play in the body, including important functions within the central nervous system.

B12 AND FOLIC ACID

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 (see page 15), is vital for communication between neurons. Even the slightest degradation or dysfunction of this can have a huge impact upon 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 so on. B12 is also involved in the production of a type of neurotransmitter called monoamines. These are involved in emotion, cognition and arousal. Folic acid is another of the B vitamins that is associated with depression. There seems to be a link between folic acid and depression and there is a chain of thought that low levels of folic acid lead to low levels of a substance called SAMe (s adenosylmethionine), that is involved in neurotransmitter production and recycling. A 2005 review study found that both low folic acid and B12 were found in depressed patients and that adequate levels of these two nutrients were associated with better responsiveness to drug treatments and better treatment outcomes .

B6

When it comes to depression, I would say that vitamin B6 is up there on the ‘essentials’ list. As a nutrient it has two vital roles to play in the brain and both are extremely pertinent to depression. Firstly, B6 is involved in the formation of myelin. Secondly, and probably most importantly, is that B6 is vital for the conversion of tryptophan into serotonin. I have highlighted the importance of consuming foods rich in serotonin (see page 19). Well, that is half the battle. Once it gets through the blood brain barrier into the brain, it then needs to go through various steps of chemical conversion to become serotonin. B6 is involved in facilitating this.

ZINC

This is a nutrient that does not often get discussed in the press in terms of depression and mental health. This is a shame, as it seems to be one of the most critical in the whole picture. It is highly concentrated in our brains, with especially high concentrations in a region of the hippocampus. One of its jobs is to maintain the protective barrier that allows the right things to enter the brain, while stopping the wrong things. Zinc also modulates aspects of the stress response and seems to play a crucial role in neurological communication. Zinc is also an essential co-factor for hundreds of enzymatic reactions. Like omega 3, zinc has encouraging evidence to support its use in depression. Zinc deficiency has been found in several studies to induce depression, reduced focus and attention . A 2013 randomised, double-blind, placebo-controlled trial that involved half of participants receiving 25mg of zinc alongside antidepressant SSRI drugs, and half receiving a placebo alongside drugs, showed that those in the treatment group had significantly reduced scores in the Beck Depression Inventory compared to the placebo group . So this vital mineral should not be neglected.

BLOOD SUGAR BALANCE

I have touched on this before (see page 36) so I won’t go overboard with it again, but blood sugar management is vital in managing depression. Keeping blood sugar levels stable influences our mood. There is no mistake there whatsoever. While not immediately associated with depression, keeping blood sugar even will make moods more stable, which will influence your outlook and the way you feel in general. The more stable and balanced you feel in terms of energy and mood, the better you will feel. Depression can affect the way in which you see the world around you. The more even you feel, the fewer extremes you will experience. OK, so there is less of a profound direct effect compared to the other nutritional elements I mentioned, but it is of value none the less.

NUTRITIONAL NUGGETS TO AID DEPRESSION:

Eat plenty of oily fish such as salmon, mackerel and herrings to get healthy helpings of pre-formed omega-3 fatty acids. I recommend at least three or four 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 and so on.

Eat plenty of green leafy vegetables, whole grains such as brown rice, eggs, lean meats and fish to get a broad spectrum of B vitamins, especially B12, B6 and folic acid. Eat prawns, shellfish and pumpkin seeds for a good-quality source of zinc.

Consider supplementing with omega 3. Look for a supplement that contains at least 750mg of EPA and 250mg of DHA and take this twice daily.