A growing understanding of the connection between our gut and our brain.

Although the interaction between our brain and gut has been studied for years, its complexities run deeper than initially thought. It seems that our minds are, in some part, controlled by the bacteria in our bowels.

The gut has defenses against pathogens, but, at the same time, it encourages the survival and growth of "healthy" gut bacteria.

Of course, these bacteria do benefit from the warmth and nutrition in our bowels, but it is not a one-way relationship - they also give back.

Some species benefit us by breaking dietary fiber down into short-chain fatty acids that we can then absorb and use. They metabolize a number of compounds on our behalf and play a role in the synthesis of  vitamins B and K.

On the other hand, recent research infers that imbalance of gut bacteria might be an important factor in inflammatory and autoimmune conditions.

The microbiome's role in health and disease is only slowly giving up its secrets. The latest and perhaps most remarkable finding is the ability that gut bacteria have to moderate our brain and behavior.

The links between our gut and brain are hormonal, immunological, and neural, via the central nervous system and the enteric nervous system, which governs the function of the gut. Collectively, they are termed the gut-brain axis.

These gut-brain conversations have been studied for some time. However, a new level to this partnership has recently been glimpsed; researchers are now considering the influence of our microbiome on the gut-brain axis. In other words, researchers are asking: do the bacteria in our gut affect our psychology and behavior?

The question is whether adding beneficial gut bacteria to an animal can make a difference. Research seems to say yes.

A study published in the Journal of Neurogastroenterology and Motility, collated the results of studies looking at the effects of probiotics on central nervous system function in both humans and animals.

They examined 25 animal and 15 human studies, most of which used Bifidobacterium and Lactobacillus over a 2-4-week period. Although, as the authors mention, translating animal studies like this into human terms is a dodgy game. They concluded: "These probiotics showed efficacy in improving psychiatric disorder-related behaviors including anxiety, depression, autism spectrum disorder, obsessive compulsive disorder and memory abilities, including spatial and non-spatial memory."

A diet high in refined carbs increased depression in post-menopausal women by 22%.

Watch out for those refined carb food binges. A new study published in The American Journal of Clinical Nutrition has revealed a diet high in refined carbohydrates may lead to an increased risk of depression in postmenopausal women. One might also assume the foods are trouble for men, but women have higher rates of depression in general.

Carbs are found in a wide variety of foods and have often been the focus of new weight-loss diets. However, the emphasis should not be on how many carbohydrates we eat, but the type.

Refined carbohydrates are contained in refined grains, such as white flour, white bread and white rice. They differ from whole-grain foods because they have been milled - a process that increases the texture and shelf life, but that also removes much of the nutritional value which includes important fiber and vitamins.

Once carbohydrates are eaten, some of the sugar is broken down into glucose that then proceeds to enter the bloodstream. The glycemic index (GI) is a metric tool used to measure and rank the extent to which our body's sugar levels are raised after eating.

Low glycemic index foods take longer to digest and break down and, therefore, enter the blood stream slowly. Thus the blood's glucose level raises more slowly over an extended period of time.

High glycemic index foods cause a more rapid rise of the blood's glucose level. Refined grains fall into this category, and it is this reason why a high glycemic index ( refined carbs) diet can lead to a host of health problems, such as insulin resistance, obesity and type two diabetes.

Foods that have some of the highest GI scores include white bread, breakfast cereals like puffed wheat and rice and corn flakes, also instant oatmeal. Pasta, crackers, cookies, pretzels and popcorn.

Doctors at Columbia University Medical Center (CUMC), NY, set out to investigate the relationship between a diet high in refined carbohydrates and depression.

The researchers analyzed data from more than 90,000 postmenopausal women who participated in the National Institutes of Health's Women's Health Initiative Observational Study that was conducted between 1994-1998. The observational study enlisted postmenopausal women between the ages of 50-79 and tracked their health over an average of 8 years.

They examined the levels of depression reported, the types of carbohydrates consumed, the GI rank and the glycemic load.

It was found that refined carb diets increased the risk of depression in postmenopausal women by 22%. Also, a higher consumption of lactose, fiber, non-juice fruits and vegetables was significantly associated with a lower chance of developing depression.

Folate and Vitamin B-12 Linked to Depression

A low intake of folate and vitamin B12 is linked to a greater risk of melancholic depressive symptoms. Typical depressive symptoms are associated with melancholic depression, such as a depressed mood. Folate helps produce chemicals that control brain functions, such as sleep, mood, and appetite, and can be found in foods like green vegetables. Vitamin B12 is also a water soluble vitamin and it plays a crucial role in the function of the brain, nervous system, and formation of red blood cells.

The results from the study showed the subjects with the highest folate intake had a 50% lower risk for melancholic depressive symptoms, compared to those with the lowest intake. And the people who had the highest vitamin B12 levels had a 3 times lower risk for melancholic depressive symptoms than those with the lowest levels.

Journal of Affective Disorders 2012

Fruits and Vegetables: Seven-A-Day for Happiness and Mental Health

Yes that's right...in this study done in the UK, happiness and mental health were highest among people who ate seven portions of fruit and vegetables a day. Now heres the problem.  Only one in ten people actually ate that many servings of fruits and vegetables and 25% ate less than one serving daily. Clearly we can do better.

–University of Warwick (2012, October 9). Fruits and vegetables: Seven-a-day for happiness and mental health. ScienceDaily. Retrieved October 10, 2012, from http://www.sciencedaily.com­