More protein is not always better, says MGH nutritionist Emily Gelsomin. Learn about how much protein you really need and the risks that come with supplements.

Most moderate exercisers do not need more than ½ gram of protein per pound of body weight. (A 150-pound person would not need more than 75 grams of protein). Americans typically consume enough protein to meet their needs.

Food fact: A 3-ounce piece of chicken (size of a deck of cards) contains about 20 grams of protein.

If you consume more protein than your body needs, the excess will be used for energy or stored as fat. This can cause weight gain if your calorie intake exceeds your needs.

Is More Protein Better?

If you consume more protein than your body needs, the excess will be used for energy or stored as fat. This can cause weight gain if your calorie intake exceeds your needs.

A Very High Protein Diet Has Risks

  • Beware of dehydration: a high protein diet causes your body to excrete excess water in an attempt to flush out urea, a byproduct of protein breakdown.
  • Take care of your kidneys: consuming too much protein may put unnecessary strain on your kidneys, which are needed to process the nutrient.
  • Bad to the bone: diets extremely high in protein, especially from animal sources, may cause calcium to be drawn out of your body, possibly putting you at risk for brittle bones later in life.

Special Considerations for Athletes

  • Endurance athletes have slightly higher protein needs (0.5 to 0.6 grams per pound).
  • Strength training athletes need 0.7 to 0.8 grams per pound.

Consuming a little protein within 30 to 60 minutes after a hard workout can help your muscles rebuild. Typically, 10 to 20 grams of protein is all you need to aid in muscle repair.

Food for thought: Consuming more than 30 grams of protein after a workout has not been shown to be beneficial. In a study done with middle-aged women, consuming 30 grams after resistance training actually decreased the availability of fat used for energy.

Try to get your protein through food as much as possible.
Try to get your protein through food as much as possible.

What About Protein Supplements?

Protein supplements have not been proven more effective at building muscle than protein from food. In the battle of whey versus soy protein, there is some evidence to favor whey, as it has more leucine to aid in repair and growth.

Taking a Supplement Can Involve Risks

  • Companies do not have to demonstrate their product is effective, or even safe, before being sold.
  • Supplements may contain high levels of potentially dangerous contaminants, such as arsenic, cadmium, lead and mercury. These heavy metals can accumulate in organs, especially if taken regularly.

The Bottom Line

Try to get your protein through food as much as possible; it is cheaper, offers a variety of naturally occurring nutrients, and is usually safe.

Protein Supplements: What You Should Know

The following ingredients—often promoted in sports supplements—have not been found to enhance athletic performance: specific amino acids, chromium picolinate, coenzyme Q10, and carnitine.

There is some controversy about whether athletes need higher levels of certain vitamins. Regardless of your exercise routine, it is not advised to exceed tolerable upper intake limits of vitamins and minerals, set by the Food and Nutrition Board of the Institute of Medicine.

Check the Label

Some ingredients found in sports supplements may even be hazardous to your health. If you are taking a supplement, here are a few things to check for on the label:

Vitamin B6: Nerve damage can occur if your daily intake consistently exceeds 2000 mg. Some reports have indicated nerves can be affected even at doses of less than 500 mg per day.

Vitamin C: Consuming excessive vitamin C may contribute to the development of kidney stones. Too much vitamin C can also cause diarrhea, nausea, vomiting and abdominal cramps. Avoid consuming more than 2000 mg per day.

Vitamin E: High amounts may cause uncontrolled bleeding. Avoid products that provide more than 1,000 mg (1500 IU) per day.

Zinc: High amounts of zinc can reduce your body’s ability to absorb copper and iron. High amounts may also reduce your good cholesterol (HDL). The upper limit of zinc is 40 mg per day.

Tryptophan: The Food and Drug Administration (FDA) and Center for Disease Control (CDC) have observed a possible link between the consumption of L-tryptophan supplements and eosinophilia myaligia syndrome (EMS), a blood disorder that can cause muscle cramping, numbness, joint pain and memory loss. In most acute cases of EMS (97%), L-tryptophan was taken prior to the development of EMS. L-tryptophan does not seem to be effective in improving athletic performance and has even been associated with several deaths.

DHEA: There are limited studies on long-term safety. DHEA has been touted to help those with autoimmune diseases and may improve immune function; however, consuming more than 50 mg per day may have serious side effects. It is speculated that high amounts of DHEA may increase risk of cancer or liver problems and may contribute to hormonal changes in the body.

Sugar alcohols (such as sorbitol, xylitol, mannitol and isomalt): Sometimes sugar alcohols are added to supplements to improve the taste of the product without adding too many calories. They can cause gas, bloating and diarrhea.

FINAL NOTE: Remember that sports supplements—as with all dietary supplements—do not need to be deemed “safe” or effective before being sold. So if you decide to use them, be sure to do your research and/or consult a medical professional.

Emily Gelsomin, MLA, RD, LDN
Emily Gelsomin, MLA, RD, LDN

Emily Gelsomin, MLA, RD, LDN, is a senior clinical nutrition specialist at Massachusetts General Hospital. As a registered dietitian, she counsels on medical nutrition therapy on an outpatient basis and works extensively with Be Fit, the hospital’s employee wellness program.

Jointly sponsored by The Clubs at Charles River Park and MGH Nutrition and Food Services, the 10-week program focuses on helping participants “Be Fit and Eat Right.” Every ten weeks, employees from different departments within the hospital compete with each other as they make a commitment to Be Fit. Through the creation of a social environment at the workplace, participants are supported to make progress in personal lifestyle changes with the help of a unique support system that includes a dedicated nutritionist and personal trainer.

Be Fit strives to create a milieu of wellness that extends beyond the 10-week curriculum by offering features to those who are not part of the intensive program. This includes the creation of Choose Well, Eat Well, a rating system designed to help both employees and patients increase awareness of healthy choices at retail eateries within the hospital. It also includes a monthly e-mail with a timely nutrition tip.