Q. Is there any reason I should avoid nightshade vegetables?
A. Nightshades, plants in the Solanaceae family, include white potatoes, tomatoes, eggplant, and sweet and hot peppers. While nightshade foods are rich in healthy antioxidants, they contain an alkaloid called solanine, a natural insect defense mechanism that’s concentrated mostly in leaves and stems. Given that humans are bigger than bugs, it would take a lot of tomato and eggplant leaves (we usually eat the vegetable part, which has lower levels) to cause solanine toxicity. Yet, if you eat enough of the leaves you’ll have an upset tummy. Steaming, boiling or baking nightshade foods reduces the alkaloid levels to nearly one-half. Avoid green patches and sprouted eyes on potatoes, as there’s more solanine there.
There is some negative buzz on nightshades, with reports that they may cause inflammation, rashes, GI upset, and migraines. Indeed, some folks may be sensitive to solanine, and may complain of arthritic joint pain and stiffness when they eat too many of these otherwise nourishing vegetables. To find out if you are one of the few, do a simple elimination diet. Go three weeks without any nightshades at all. Then, add them back in and see if you have a reaction. If you do, expand your diet to include other nutrient-rich, anti-inflammatory fruits and vegetables, as well as healthy monounsaturated fats, fish, legumes, nuts and seeds. If you don’t have a reaction, then bon appétit—enjoy the deliciousness of nightshades.
—Diana Cullum-Dugan, R.D., L.D.N., R.Y.T.
Q. Do mulberry leaf supplements have any real health benefits?
A. Mulberry leaf has been used for centuries in Chinese and Japanese cultures as traditional medicine to treat a wide variety of health concerns, from the common cold to diabetes. Mulberry leaf—available in tea and supplement forms—exhibits powerful antioxidant and anti-inflammatory properties. And emerging research indicates that mulberry leaf may possess specific health benefits, including controlling blood glucose levels and protecting the heart against oxidative stress. Published studies in the American Journal of Clinical Nutrition and the Journal of Nutritional Science and Vitaminology report that mulberry leaf may help control elevated blood sugar by slowing the rise in blood sugar that occurs after consuming a carbohydrate-rich meal. In addition, mulberry leaf may protect your heart by decreasing serum levels of triglyercides, total cholesterol, and LDL (“bad”) cholesterol. Keep in mind that while this research is encouraging, we need more studies to confirm these benefits. And your best bet—as always—is to prevent chronic disease by eating a balanced diet, exercising regularly, and managing stress in healthy ways.
—McKenzie Hall, R.D.