People could even be ready to join a diabetes prevention program. In reality, a overview of research in the Journal of Geriatric Cardiology means that plant-ahead diets like vegetarian, semi-vegetarian or vegan can serve as a part of a holistic treatment and prevention of sort 2 diabetes. This is particularly of concern with vitamins A and D, which can be toxic if taken in excess. If taken in excess they are readily excreted within the urine, though there is potential toxicity even with water-soluble vitamins