Large doses of vitamin E may help normalize retinal blood flow problems and improve kidney function in people with diabetes, according to researchers at the Joslin Diabetes Center in Boston.
According to the August issue of Diabetes Care, retinal blood flow increased to a near-normal rate and kidney function also improved in type 1s who took 1,800 IU of vitamin E.
Researchers randomly assigned 36 patients with type 1 diabetes and nine nondiabetic control subjects to 1,800 IU of vitamin E per day or a placebo for four months. The vitamin E was natural d-tocopherol acetate dissolved in edible vegetable oil. The placebo contained soybean oil. The subjects then switched pills for an additional four months. Practitioners were unaware which group had the real thing.
Dr. George L. King of Joslin reports that after four months, retinal blood flow was significantly increased in type 1 patients after vitamin E treatment. He adds that vitamin E treatment decreased creatinine levels and normalized kidney function in type 1 patients. He says that HbA1c was not affected by the vitamin E dosage in type 1 patients.
“What we found is that a low dose of vitamin E is an antioxidant,” King says. “Higher doses have the ability to inhibit enzymes that are involved in diabetic complications.”
Sixty Times the Recommended Daily Allowance
In an editorial accompanying the report, Dr. Sushil K. Jain of the Louisiana State University Medical School in Shreveport says that the dosage of vitamin E used in the study was 60 times greater than the recommended daily allowance of 30 IU per day, and that not much is known about potential problems that could arise from such a high level.
On a similar note, Vincent Curry of Cannon Beach, Oregon, says that he took 400 IU per day of vitamin E for about six months and developed swelling and blisters on his lower legs. When he stopped taking the high dosage, the swelling and blisters went away.
“We didn’t see anything like that in our studies,” says King, who recommends that people with type 1 diabetes take 500 to 700 IU of vitamin E per day.
Vitamin E and Type 2 Diabetes
In a previous study conducted on people with type 2 diabetes, researchers at Sant’ Anna Hospital in Como, Italy, discovered that vitamin E supplementation could aid in the prevention of mild to moderate peripheral neuropathy in individuals with type 2 diabetes. According to the November 1998 issue of Diabetes Care, patients receiving 900 IU per day of vitamin E for six months demonstrated increased motor nerve velocity when compared to a placebo.
Larger Study Needed
King admits that a larger clinical study is needed to further explore the benefits of vitamin E in people with type 1 diabetes. However, he says, since vitamin E is not patentable, most private drug companies will not sponsor this type of study.
“Nobody wants to sponsor a $430 million drug trial if they can’t patent the drug themselves,” says King. “If we run a large study, we can determine whether a trial is needed. Then, we can recommend what vitamin E dose to take, and can conclude that large doses of vitamin E are beneficial to the eyes and kidneys of people with type 1 diabetes.”
Jane DeMouy, deputy director of the communications office at the National Institutes of Health (NIH) confirms that King has spoken with NIH staff about the possibility of a trial, and says he was encouraged to apply for a grant to fund further studies in an animal model.
“As I understand it, the data he has involved very small numbers so [the NIH] wanted to see something more definitive,” says DeMouy. “That would be the usual process for seeking funding to demonstrate the efficacy of a treatment. His study would then be subject to the same scrutiny that any other study is subject to.”
25 Pounds of Cereal a Day
King recommends getting the vitamin E you need from a supplement.
“You can’t get these high amounts of vitamin E from a diet, unless you eat 5 pounds of wheat germ or 25 pounds of cereal a day,” says King, “There is the L type of vitamin E and the D type. Only D appears to be potent. The L form is not active, whereas D is. When you buy it in the store, it is mainly a mixture of the two.”