In his book Serve to Win, Novak Djokovic describes how a gluten- free diet helped make him the world's No. 1 tennis player. Can this diet help me?

In his book Serve to Win, Novak Djokovic describes how a gluten- free diet helped make him the world's No. 1 tennis player. Can this diet help me?

Stephanie Moleski is a gastroenterologist at Thomas Jefferson University Hospital.

A: Serve to Win describes how, in 2010, Djokovic met with fellow Serb and nutritionist Igor Cetojevic, who believed that Djokovic's recurrent shortness of breath and near collapse in matches were from his diet. To make the point, Cetojevic asked Djokovic to hold a piece of bread in his left hand against his stomach while he pressed down on the outstretched right arm. Djokovic was much weaker while holding the bread. This unproven test is cited as evidence that he is sensitive to gluten.

Celiac is an autoimmune disease, triggered by the protein gluten found in wheat, barley, and rye. When such a person eats gluten, it damages the lining of the small intestine and interferes with nutrient absorption. We have very accurate antibody tests for this, which are then confirmed by a biopsy of the small intestine.

If a patient is gluten-sensitive, but the labs are negative, we suspect non-celiac gluten sensitivity.

This is why Djokovic avoids gluten. These patients have celiaclike symptoms, but no antibodies or intestinal damage. They may have diarrhea, gas, and bloating with ingestion of gluten, as well as joint pain, head- aches, and "brain fog."

There are no recommended tests for this. Some doctors offer saliva, blood, or stool studies (and Cetojevic's holding bread/strength test), but none is validated. To best diagnose this, doctors ask patients to exclude gluten. If you suspect celiac or gluten sensitivity, see your doctor before starting the diet. It's unlikely it will make you great at tennis, but treatment could relieve some symptoms.