Dawn Earnesty is a PhD student in MSU Food Science and Human Nutrition and an Extension Educator at MSU Extension.
Do dark colored foods really have more nutrients?
This depends on the type of food that you're thinking about. When it comes to types of lettuce, you want to try to consume dark leafy greens instead of iceberg lettuce. Oftentimes there are more antioxidants in darker vegetables. For example, black beans contain more antioxidants than white beans.
With that being said, white beans have higher levels of iron, potassium, and protein than black beans do. Red and orange vegetables, such as red and orange peppers, are higher in Vitamin C than most other vegetables. Green vegetables tend to be higher in iron, especially dark leafy greens such as kale or spinach.
Dark green leafy vegetables tend to be higher in protein as well. It is important to eat a variety of colors to ensure that you're consuming adequate nutrition, so try to incorporate different colors into your meals each day.
Are bananas more nutritious as they ripen? Why?
This is not true, however, ripe bananas can be easier to digest. Some studies show that there are nutrient losses that occur when they ripen, however, there are higher levels of antioxidants. They also have higher sugar content when they ripen.
How much vitamin content is destroyed as vegetables are steamed?
There are some vitamins that are lost through the steaming process, however, this method of cooking results in the lowest amount of vitamin loss when compared to microwaving, boiling, or stir-frying.
Vitamin C and Vitamin B compounds are the vitamins that are most commonly lost throughout the cooking process because they are easily broken down by heat. Try to keep the cooking time to a minimum to help preserve the nutrients, steaming the vegetables just until tender.