One of the most enjoyable and satisfying parts of being a dietitian is talking to customers who take a keen interest in what they eat. But even those who are shopping for healthy foods don't necessarily know how to best prepare them so that they keep the foods' beneficial substances intact.
Plenty of information details how to keep vitamins in foods. For instance, it's best to shield the food from light and air and cook it in a minimal amount of water. But little information is published on how phytonutrients, such as carotenoids, flavonoids and isoflavones, fit into the equation. They are linked with heart health, cancer prevention, brain power and more, and their health-boosting benefits are often what drives customers to buy them.
What we know about phytonutrients is in its infancy. We have seen just the tip of the iceberg in terms of which phytonutrients exist (chances are there are tens of thousands), much less how they respond to processing and cooking. However, based on the research that has been done, there are three key messages you can give your customers:
- Raw or fresh isn't always best. Some foods offer better nutrition after being cooked. For example, heat destroys enzymes in soybeans and other legumes, making the protein in these foods digestible and usable by the body. Cooking can also destroy "antinutrients" which, as the name suggests, block the absorption of beneficial substances. And heat can also soften or break open the cell walls of foods, allowing certain phytonutrients to be more easily released and available for absorption. For example, one study found the heart-healthy antioxidant content of broccoli, asparagus, cabbage and peppers increased more than 100 percent (some more than 400 percent) after being steamed. A word of caution, though: Overcooking foods can diminish their beneficial properties, so steam until crispy, not soggy.
- Cooking with fat can lead to better nutrient absorption. For years we functioned under a low-fat, no-fat approach to eating well, but that idea is changing. Research now shows that certain nutrients in foods are more available to our bodies if we include fat (albeit healthier fats, like the kind found in avocados and olive oil) in our diets. Case in point: vitamins A, D, E and K. Each of these vitamins requires fat for absorption. So do carotenes, such as beta-carotene, found in orange fruits and vegetables and dark green vegetables; lycopene, found in tomatoes; and lutein and zeaxanthin, found in yellow and green vegetables. One analysis of carrots found that five times more carotenes were available for absorption if the carrots were cooked in a small amount of oil versus eaten raw.
- It's all about synergy. The back-and-forth, "it's good, it's not good" news we hear about different nutrients often stems from studies that look at nutrients in isolation. But a growing body of research shows there is an additive and synergistic relationship between nutrients. Vitamins, minerals and phytonutrients appear to complement and play off one another. When a nutrient is plucked from a food source and consumed by itself, it may yield little to no beneficial effect. In isolation, it may lose its activity or behave differently than it would in its natural environment. For example, laboratory tests suggest that anthocyanin, a phytonutrient in berries that protects against inflammation and atherosclerosis, is better able to deliver its beneficial properties if it is digested with another food, like bread, cereal or even ice cream. These foods keep the nature of anthocyanins from breaking down.
Shoppers care about the integrity and wholesomeness of the foods they buy, and I think that interest will continue to grow as more research reveals how foods may affect heart health, the risk for cancer, Alzheimer's disease, diabetes and more. In addition to stocking whole, health-boosting foods, helping customers learn how to make these foods even more valuable through preparation is a great service.
Susan Moores, R.D., runs SDM Communications, a consulting firm specializing in food and health issues. Contact her at [email protected] or 651.653.4794.
Natural Foods Merchandiser volume XXVIII/number 12/p.40