Are Vegetarians More at Risk for DCS?

A study by two Dutch medical researchers published in the May/June issue of the Underwater Hyperbaric Medical Journal is significant for vegetarian divers.

A 36-year-old male dive instructor made one dive for 60 minutes to 60 feet, sat out for two hours, then made a second dive for 52 minutes to a maximum depth of 70 feet. His dive computer gave a decompression stop for eight minutes at 10 feet, which he did. Forty-five minutes after the dive, he noticed tingling in his feet and his left hand, weakness in both legs, pain in his left elbow and a general tiredness. He hydrated by drinking 500 mL of water and during the six-hour transfer to the hyperbaric chamber, he breathed 100 percent oxygen. Upon arrival, he was treated in the chamber and had several subsequent sessions. While his symptoms gradually lessened, in between there was a relapse of his sensory symptoms and weakness of his lower legs. This persisted after the last treatment.

On the fourth day of the treatment, researchers learned he was a vegetarian and diagnosed him with macrocytic anemia. They administered cyanocobalamin intramuscularly and put him on a three-month protocol. Within four weeks, he recovered and resumed diving after six months. He was advised to take multivitamin tablets with B12 on a daily basis. The researchers concluded that the diver had DCS initially and was especially at risk because of a vulnerable spinal cord due to a long-lasting deficiency of vitamin B-12. They also believe some of the symptoms in the post-treatment period were manifestations of a B12 deficiency enhanced by DCS.

The researchers noted that although vegetables are generally devoid of vitamin B12, strict vegetarians almost never develop a clinical deficiency, as only five miligrams of vitamin B12 are needed daily and an adequate amount is available in legumes. However, Vitamin B12 deficiency affects the spinal cord, brain, optic nerves and peripheral nerves. The onset of manifestations is gradual over months. The spinal cord is usually affected first and often exclusively. Patients first notice general weakness and paresthesias consisting of tingling, a “pins and needles” feeling and other vaguely described sensations. As the illness progresses, the gait becomes unsteady and stiffness and weakness of the limbs develops, especially in the legs.

The researchers “do not believe that vegetarians in general are at risk for DCS but they should be aware of their nutritional status, particularly regarding vitamin B12.”

“Decompression Sickness in a Vegetarian Diver: Are Vegetarain Divers at Risk? A Case Report”, by Robert A. Van Hulst and Wim Van Der Kamp, Undersea and Hyperbaric Medical Journal, Vol. 37, No. 3, pages 181-184