Three questions: Organic produce, iron and iodine, and tryptophan

Q: I’m trying to save money at the grocery store. Are organic fruits and vegetables really worth the higher price?

— SARA H., Roswell

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A: The cost of organic produce can be quite high, so you might want to consider a few options. First, look for locally grown organic produce by visiting farmers markets. This will get easier once summer arrives. You can also check out the Environmental Working Group’s new release of the “dirty dozen” and “clean 15.” This group rates pesticide residues on fresh produce and claims you can lower your pesticide exposure by about 80 percent by avoiding the 12 most pesticide-contaminated fruits and veggies. Consider buying organic fruits and veggies listed on the “dirty dozen list.” Lastly, this summer, plant a small home garden or if space is limited, a container garden.

Q: Is watermelon a good source of iron? Is sea salt a good source of iodine?

— CHERYL M., Atlanta

A: Watermelon is not a good source of iron. Most fruit doesn’t contain any iron, with the exception of some dried fruit, like raisins. Watermelon is a good source of potassium, a mineral needed to help regulate blood pressure. It also contains lycopene, a plant nutrient that is tied to reduced risk of prostate cancer and heart disease. Lycopene is found in other red and pink food like tomatoes, red bell peppers and pink grapefruit. Sea salt does not contain iodine. Some table salt has added iodine; this began at a time when iodine deficiency was more common than it is today. Now you don’t need to worry about getting sufficient iodine through salt because iodine is present in other food and is used as a dough conditioner in bread. Sea salt does contain as much sodium as table salt, so if you are trying to reduce salt intake, sea salt won’t help you do that.

Q: Does skim milk have the same amount of tryptophan as whole milk? What about soy milk?

— E. DANIELL, Fayetteville

A: Yes, soy milk, skim milk and whole milk all contain about the same amount of the amino acid tryptophan, about 115 milligrams per cup. Tryptophan is often thought of as a sleep inducer, and because turkey is high in tryptophan, some people think that the Thanksgiving meal induces “turkey coma.” The truth is that all protein-containing foods are high in tryptophan, but this amino acid might make you sleepy only if you take it on an empty stomach — not something we do at Thanksgiving.