Defining mental illness: An interview with a Mayo Clinic specialist

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Defining mental illness: An interview with a Mayo Clinic specialist

Mental illness — A psychiatrist puts it all into perspective, from types to treatments.

A diet that has extended the life span of worms, flies and rats is capturing the interest of humans. Believers say the calorie restriction diet, which involves eating less, while still getting enough vitamins and nutrients, makes them healthier. And they hope calorie restriction extends their lives.

But just because a diet works in animals doesn't necessarily mean it will work for people. And even if a limited calorie diet was found to extend your life, would you be willing to stick to it?

Scientists have their doubts about the viability of the calorie restriction diet in a Western culture where overweight and obesity seem to be the norm. Still, calorie restriction research may give doctors clues about the aging process and how its effects may be slowed.

What is calorie restriction?

Calorie restriction is the practice of eating less than your body needs to maintain your normal weight. Exactly how much less a person eats on a calorie restriction diet varies. In research studies, people practicing calorie restriction ate 20 percent to 25 percent less than their bodies needed. For example, a person who needs 2,000 daily calories for weight maintenance might eat 1,500 to 1,600 calories a day on a calorie restriction diet. People who follow a calorie restriction diet do so in hopes of slowing the aging process and extending their lives.

But beyond restricting how much food they eat, people who subscribe to calorie restriction carefully monitor their food intake to ensure they're getting all the vitamins and nutrients they need. This can mean choosing more foods that are full of nutrients, but low in calories, such as vegetables and whole grains.

Interest in calorie restriction has grown as studies show the diet can extend the lives of animals. Only limited studies have been conducted in people.

Should you try calorie restriction?

Very little is known about the long-term effects of calorie restriction in people who have a healthy weight. If you're interested in trying a calorie restricted diet, discuss this with your doctor. He or she can discuss the possible benefits and risks of a calorie restriction diet. Eating enough vitamins and nutrients can be difficult when you're eating less food, so consulting with a nutritionist may be helpful. He or she can help you determine what types of foods can provide you with the nutrition you need.

Sticking to a calorie restriction diet isn't easy. In some clinical trials, participants had their meals prepared by researchers, attended weekly support groups and had counseling sessions to help them stick to the protocol. Outside of a clinical trial, you don't have that same support, so you may have more trouble sticking to the diet.

You might find it easier to use exercise to help achieve your calorie restriction goals, as some participants have done in clinical trials. Rather than cut their caloric intake by 20 percent, for example, some participants cut their diets by 10 percent and used exercise to make up the difference. For instance, a person who needs 2,000 daily calories to maintain his or her weight might eat 200 fewer calories and exercise enough to burn 200 calories each day.

If you're overweight or obese, calorie restriction may be one strategy you can consider to help you achieve a healthy weight. Discuss this with your doctor.

Is calorie restriction the future of anti-aging therapy?

Calorie restriction studies may help researchers better understand the aging process, and they may provide clues for developing new anti-aging drugs. Researchers hope to study how calorie restriction works on the body so that drugs may be developed to work in the same way.

What is testosterone?

Men's bodies produce the hormone testosterone in their testes. In men, testosterone helps maintain:

  • Bone density
  • Fat distribution
  • Muscle mass
  • Muscle strength
  • Red blood cell production
  • Sex drive
  • Sperm production

Your doctor can prescribe a synthetic version of testosterone. Testosterone therapy using testosterone replacement medications may be necessary for men who have very low levels of testosterone (hypogonadism). Testosterone therapy medications are available as injections, patches and gels.

The influence of testosterone in adult men

The influence of testosterone in adult men

The male hormone testosterone plays an important role in the development and maintenance of typical masculine physical characteristics.

What happens to your testosterone level as you age?

Your body's testosterone level peaks during adolescence and early adulthood. Starting around age 40, your body produces less testosterone. For most men, testosterone levels decline modestly.

What could testosterone therapy do for men with normal testosterone levels?

Some men believe that taking testosterone medications may help them feel younger and more vigorous as they age. But while studies show that testosterone therapy can restore your testosterone level to that of your youth, it isn't clear that there's any benefit to this. And it isn't clear if a higher testosterone level can help you live longer.

Few rigorous studies have examined testosterone therapy in men with healthy testosterone levels. Some small studies have revealed unclear results. For instance, studies found that healthy men who take testosterone medications saw their muscle mass increase, but in most studies the men weren't any stronger after testosterone therapy.

Last Updated: 08/17/2006
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