As the holidays near and many people are planning to spend more time in the kitchen, it’s a good time to address several commonly asked questions related to cooking and food.
Here are some questions I've received over the years:
True or false: I should avoid cooking with aluminum foil because aluminum can leach into food, which can lead to Alzheimer's disease.
False. Cooking with aluminum foil or in aluminum pots was once thought to be possibly linked to the development of Alzheimer’s disease, but studies have not borne this out. A more important reason not to cook in aluminum is that it is a poor conductor and retainer of heat.
True or false: The chemicals in nonstick cookware cause health conditions such as cancers.
This is a complex question. Overall, nonstick pans manufactured since 2013 are thought to be safe, except at high temperatures. The nonstick coating contains PTFE (polytetrafluoroethylene), a chemical considered safe below 500 degrees Fahrenheit. Above that temperature, its fluoropolymers start to break down and release toxic gases that are lethal to birds and cause a flu-like illness in humans called polymer fume fever.
To avoid heating your nonstick cookware above the safety zone, try cooking on only low or medium heat on the stove and do not preheat an empty pan. Heavier pans tend to heat more slowly, so avoid lightweight, cheap pans that will heat too quickly. Also, make sure to use ventilation. Finally, if your nonstick surface gets scratched or chipped, replace the pan. (Avoid scratches by using non-metal utensils on nonstick surfaces.)
If you are not sure you’ll be able to follow these guidelines, it might be time to consider other nonstick surfaces, such as ceramic or cast iron.
Note: Some nonstick pans used to contain another chemical, PFOA (perfluorooctanoic acid), which is linked to many health conditions, including cancers. However, these products have been PFOA-free since 2013.
True or false: It is unsafe to reheat food in plastic wrap and plastic food containers.
True, for the most part. The most toxic chemicals that are used to manufacture certain plastics are BPA (bisphenol-A), added to make clear, hard plastic; and phthalates, added to make plastic flexible. These chemicals are thought to be endocrine disrupters — substances that mimic human hormones — and can cause cancerous tumors, birth defects, and other developmental disorders.
When food is wrapped in plastic or placed in a plastic container and microwaved, BPA and phthalates may leak into the food, especially with fatty foods such as meats and cheeses. To be safe, reheat your food in glass containers and cover with a paper towel, not plastic wrap.
Bonus Cooking and Nutrition Questions
True or false: Raw food is healthier than cooked food.
It depends. Cooking food can add to its nutritional value — for example, cooking makes the antioxidant lycopene more bioavailable from tomatoes, and cooking kale improves its ability to reduce cholesterol. However, overcooking vegetables will reduce antioxidants and vitamins.
In general, lightly cooking in minimal water (such as steaming or stir-frying) is the best way to maintain nutrients when cooking most fruits and vegetables.
True or false: Microwaving foods zaps nutrients.
False. Microwaving is actually one of the best cooking methods for retaining the nutrients in vegetables, for the reasons above — it’s quick, minimizing the time that enzymes can destroy vitamins. And it doesn’t expose the vegetable to liquid water or water vapor, which leach out water-soluble vitamins and minerals.
True or false: It's important to detox or reboot your system periodically.
False. Cleanses and detox systems are a marketing ploy. Your body does a good job of doing that on its own, as long as you're eating a healthy diet. This means limiting processed food; fruits and vegetables are particularly good choices for "rebooting" your digestive system or rebuilding a healthy microbiome (gut flora).
True or false: Spicy foods burn calories.
True, but minimally. Certain spices can increase metabolic rate by temporarily increasing body temperature. Capsaicin, the compound that gives red chili pepper its powerful kick, does this the most, but black pepper and ginger have similar effects. The increase in metabolic rate may be up to 8 percent. Another way in which eating spicy food can lead to reduced caloric intake is by acting as an appetite suppressant. Whether this is by curbing appetite or by burning the tongue is not clear!
Do you have any other cooking-related questions you'd like answered? Leave them in the comments!
Contributor: Linda Shiue, MD