Quick Dips

Stress and Nutrition

It's a common belief that stress has an effect on the human body and its functioning, but Lincoln University researchers are hoping to find out just what those effects are and whether they are always bad.

"Stress is part of life and we can't always eliminate it. But correctly regulated, the stress response processes are actually there to serve a positive and useful purpose," says researcher Dr Sue Alexander.

The work could have wide application in human health and give insights into such illnesses as obesity, eating disorders, depression, chronic fatigue syndrome, the morbid loss of appetite seen in cancer and AIDS patients, as well as the burnout experienced by people such as athletes.

"We can already identify many of the external circumstances that cause stress," says Alexander, "but it is important that we find out about the physiological and chemical processes involved in the stress reaction."

The research aims to sort out the interactions between nutrition and stress hormone secretion.

"The stress process helps us in a whole range of circumstances including emergencies. Stress can stimulate us to superhuman feats of achievements such as lifting a car off a crushed person. So it's not all bad."

The subject of stress has interested Emeritus Professor Cliff Irvine for many years, stirred first by an early involvement with horses and the pressure put on them during training and racing. As an endocrinologist studying hormone systems, he has been well placed to investigate this phemomenon because hormones play a central role in the body's response to stress. The current study into human response has been funded by the Health Research Council.

Research into the control of the stress response is important both to veterinary and human medicine because it is well known that stress can impair health in race horses and people. It does this by altering the concentration of hormones in the blood and one consequence of this is that the immune system is disrupted.

"Too much of the hormone cortisol over-suppresses the immune sysptem which makes the body vulnerable to pathogens and carcinogens, and too little cortisol permits excess antibody production which raises the risk of inflammatory and auto-immune diseases, such as rheumatoid arthritis."

Finding out about the levels of hormones in both unstresses and stressed conditions is a very important part of any work in this area. This work is the first to use a non-surgical technique for monitoring bran hormone levels in the fully conscious horses and obtaining baseline readings.

"Horses respond to a variety of stresses just as humans do. They have one stomach and run on glucose just like us."

The current wisdom points to human stress responses having a close link with a person's nutritional state -- whether they have eaten or not. No one has yet been able to measure and interpret the brain responses in an unstressed animal so we are the only ones who can prove if the theory is right or wrong," says Alexander.