Doctor’s Tip: Dr. Greger’s daily dozen — other vegetables

Doctor’s Tip

This column is another in a series about Dr. Michael Greger’s daily dozen, described in the second half of his book “How Not to Die.” So far, we have covered greens, green smoothies and cruciferous vegetables.

“Other vegetables” is another one of Dr. Greger’s daily dozen, and his favorites are artichokes, asparagus, beets, bell peppers, carrots, corn, garlic, mushrooms, okra, onions, purple and yellow sweet potatoes, pumpkin, sea vegetables (arame, dulse and nori seaweed), snap peas, squash, tomatoes and zucchini. He recommends two servings a day, and examples of serving sizes are 1/2 cup of raw or cooked nonleafy vegetables, 1/2 cup of vegetable juice and 1/4 cup of dried mushrooms.

In order to keep his daily dozen at 12 instead of a baker’s dozen (13), Dr. Greger includes mushrooms with other vegetables, even though mushrooms are a fungus rather than a vegetable. Mushrooms have important immune-enhancing and cancer-preventing benefits, and should be eaten two or three times a week. They should not be eaten raw, due to a toxin that is destroyed by cooking. Morel mushrooms have a particularly high level of this toxin, which even when cooked can react with alcohol, so Dr. Greger doesn’t recommend that variety.

The Allium family of vegetables shares the spotlight with cruciferous vegetables (discussed in last week’s column) for cancer prevention. It includes onions, garlic, leeks, chives and shallots. In the laboratory, garlic, for example, has been shown to destroy cancer cells without having any adverse effects on normal cells. Garlic and onions in particular have been shown in human studies to help prevent several types of cancer. Dr. Greger and other nutrition experts recommend eating some Allium vegetables every day.

Sweet potatoes (along with the cruciferous vegetable red cabbage) have the most nutrients per dollar of any food on the planet. They are healthier than white potatoes, but purple potatoes offer the most health benefits. Purple sweet potatoes, especially eaten with the skin, have been shown to have super antioxidant and anti-inflammatory power, and have been shown to lower blood pressure.

Some vegetables have been shown to prevent prostate cancer, others to prevent brain cancer, others breast cancer, others heart disease, etc. Pharmaceutical and supplement companies are always trying to come up with the “silver bullet” ingredient that they can put in a pill and sell. However, the power of food comes not from a single ingredient or a single super food, but from eating a variety of vegetables, fruit, whole grains, nuts, and seeds — what Dr. Caldwell Esselstyn calls “a symphony of whole plant foods,” with different ingredients and the interaction of these ingredients with each other offering different health benefits.

What’s the best way to eat vegetables? For the most part, you get most nutrients from veggies if you eat them raw, and a green smoothie is one way of doing that (75% tightly packed greens with some cruciferous vegetables and flax meal and 25% fruit). However, there are exceptions. For example, you get more vitamin A if you cook carrots; you get more lycopene from tomatoes if you cook them. Steaming may improve the bile acid-binding capacity of vegetables, which may help lower breast cancer risk. In general, though, the best way to eat vegetables is whatever way you will eat the most.

Six cooking methods were studied — baking, boiling, frying, griddling (cooking on a thick frying pan with no oil), microwaving and pressure-cooking. Clearly, we should avoid deep frying, which results in formation of carcinogens in both meat and plant foods. Although it depended somewhat on the vegetable, griddling and microwaving resulted in retention of the most antioxidants and other nutrients.

When it comes to vegetables, here’s the bottom line: It’s important to eat a variety of deeply colored vegetables for optimal health. An important side benefit is that eating a variety of fiber-containing whole plant foods results in an optimal gut microbiome, which also contributes to good health.

One other point, given that last Friday was Earth Day: Eating at the bottom of the food chain by eating unprocessed plants has the least environmental impact.

Dr. Feinsinger is a retired family physician with special interest in disease prevention and reversal through nutrition. Free services through Center For Prevention and The People’s Clinic include: one-hour consultations, shop-with-a-doc at Carbondale City Market and cooking classes. Call 970-379-5718 for appointment or email

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