JERUSALEM, June 1 (JTA) — Memory loss and dementia among the elderly may be caused by a deficiency of vitamin B-12, according to an Israeli researcher. Tel Aviv University professor Uri Zeligson said that insufficient levels of the vitamin can lead to damage of the nervous system. He said that many doctors are insufficiently aware of the role the vitamin plays and do not give patients the appropriate treatment. Recent studies have found that 4 to 16 percent of geriatric patients suffering from memory loss and dementia had vitamin B-12 deficiencies. Zeligson said that these symptoms could develop in people who observe strict vegetarian diets and do not eat meat, dairy products or eggs.