Probiotics may indeed help with constipation

Q. Are probiotics really helpful in treating constipation?

A. In some people probiotics do seem to help, especially when constipation is part of a condition known as Irritable Bowel Syndrome (IBS), but they are far from universally effective.

Evidence is growing that probiotics - live active cultures of health-promoting bacteria - may offer a variety of health benefits. The most consistent benefits suggest that probiotics may help control diarrhea following antibiotic treatment. Some studies show probiotics may help in dealing with inflammatory bowel diseases, like ulcerative colitis and Crohn's, and play a role in reducing risk of colon cancer.

There are many variables that reflect on how probiotics influence a person's condition. Different types of probiotic bacteria clearly have different effects. Individuals will almost surely respond differently to the same probiotic bacteria, depending in part on the kinds of bacteria already living in their digestive tract and in their overall diet.

For example, probiotic bacteria might multiply and produce beneficial results more quickly if there is enough dietary fiber on which the bacteria can "feed." Eating a high-fiber diet, drinking plenty of fluids and getting regular physical activity are all factors that may help probiotics be more effective in overcoming constipation.

Q. What is tahini, and is it healthy?

A. Tahini is a mixture of toasted sesame seeds and olive oil, pureed to a consistency like peanut butter. It is especially common in Middle Eastern cuisine, where tahini is a key ingredient in hummus (a puree made with chickpeas, garlic and lemon juice) and baba ghanoush (a puree made with eggplant, garlic and lemon juice).

Nutritionally, it also has a lot in common with peanut butter: almost 80 percent of its calories come from fat, but little of it is saturated fat (the kind that raises blood cholesterol). So while it is a healthy choice, just be mindful that tahini is concentrated in calories, with about 170 in a two-tablespoon serving, and enjoy it in small amounts.

Q. I am told that quercetin is a compound that helps prevent cancer. What foods can I find it in if I don't want to take it as a supplement?

A. Quercetin is a phytochemical - a natural compound found in plant foods - that belongs to a large family of compounds called flavonoids. Laboratory studies suggest that quercetin can provide both anti-cancer and heart-protective effects. It seems to serve as an antioxidant and anti-inflammatory agent, as well as helping to control abnormal cell growth and deactivate carcinogens.

But you are quite right to be thinking of food as the best source. It's not clear how well our body absorbs flavonoids like quercetin. Also, the benefits we see in people who eat diets high in quercetin and other flavonoids may come from quercetin interacting with a whole host of nutrients and phytochemicals.

Many quercetin supplements provide much larger amounts than found in the diet. That may sound like a good thing, but research in the last few years has been showing that we can get too much of a good thing when it comes to antioxidant nutrients.

Foods that provide the most quercetin are onions, apples (with the skin) and freshly brewed tea. These are high-level sources, but so are asparagus, green peppers, romaine and leaf lettuce, cherries, pears and blueberries, blackberries and cranberries. Focus on a variety and abundance of vegetables and fruits, and you'll get quercetin and a lot more.