Topic summary contributed by volunteer(s): Randy

The World Health Organization blames millions of deaths a year on inadequate fruit and vegetable intake (see also here, here). Thankfully, the 2010 USDA Guidelines introduced MyPlate, which caught up with the science and recommended a shift to a plant-based diet that emphasizes fruits and vegetables (see also here). Nine servings of fruits and vegetables a day are now recommended (see also here). But based on the 2005 Dietary Guidelines, 9 out of 10 Americans did not reach the minimum recommended daily serving for vegetables. In terms of nutrients per calorie, vegetables are the healthiest food source (greens especially). And variety is important because different vegetables have different phytonutrients (see also here). A healthy eating index can be calculated based on the phytonutrient content of your food (phytonutrients come from plants). Even a low carb diet, if based on plant foods, has been found to be health-promoting.

The World Cancer Research Fund’s official recommendation for cancer prevention is to choose a plant-based diet rich in fruits, vegetables, nuts, and beans (see also here, here). The cruciferous and allium families of vegetables may be the best for cancer prevention. Higher levels of green tea consumption in Asia are thought to be responsible for lower lung cancer rates, despite higher smoking rates. Green tea also induces a relaxed state of mind. Similarly, lignans (from flax seeds) are thought to be protective against breast cancer and may improve survival. And mushrooms may even be effective in the treatment of breast cancer.

Broccoli appears to protect against DNA damage. Sulforaphane, a phytonutrient produced by cruciferous vegetables such as broccoli, may inhibit breast cancer stem cells (see also here, here). It is likewise thought to prevent lung cancer metastases and increase bladder cancer survival rates. It also boosts the liver’s detoxifying enzymes. The safe upper limit for broccoli consumption is probably about 100 cups a day (see here, here, here). Luckily, growing your own broccoli sprouts is one of the most economical vegetable sources.

Greater fruit and vegetable consumption may also lower the risk of dementia, abdominal aortic aneurysm, macular degeneration, glaucoma, erectile dysfunction, heart disease, and COPD (see also here).

Purple cabbage (see also here), beets, and artichokes are very high in antioxidants (see also here). And the more antioxidants you eat, apparently the more you benefit. On average, plant foods have 64 times more antioxidants than animal foods (see also here). Antioxidants are also thought to increase stool size, which appears to decrease cancer risk. And the best cooking method for preserving the nutrients in cooked vegetables has been found to be microwaving. Cooking is preferable to raw for some vegetables as cooking can boost the absorption of certain phytonutrients.

Vegetables (especially greens) contain nitrates, which treat hypertension, high blood pressure, and protect against heart attacks (see also here, here, here, here). Kale has been found to boost the immune system. Kale juice also reduces bad cholesterol, boosts good cholesterol, and is rich in antioxidants. Carotenoids (found in greens such as kale) have been found to improve the appearance of skin (see also here). Lutein and zeaxanthin, phytonutrients protective against cataracts and macular degeneration, can be found in high levels in kale, collard greens, and carrots. Purslane has been found to effectively treat oral lichen planus. And beets have been found to improve athletic performance (see here, here, here, here, here, here).

Regular carrots are healthier than baby carrots, red leaf lettuce is the healthiest lettuce (iceberg lettuce is one of the least nutritious vegetables), and red onions are the healthiest onion.

There may be some obesogens in conventionally grown fruits and vegetables because some of the chemicals are used as fungicides (although relatively little compared to fish). The benefits of fruit and vegetable consumption well outweigh any risks. Kimchi, however, has been associated with an increased cancer risk. Moderate alcohol consumption by relatively healthy people appears to have no effect on health. And Juice Plus+ may just be an overpriced vitamin supplement that does not likely provide the same benefits as fruits and vegetables.

See also the related blog post: Using Greens to Improve Athletic Performance

Image Credit: Hans Splinter / Flickr. This image has been modified.