Researchers have known for years that a diet rich in fruits and vegetables can help prevent illness and prolong life. They often point to cultures whose diets contain mostly plant-based foods, noting that these groups tend to have lower rates of heart disease, cancer, diabetes and other illnesses. The health benefits of fruits and vegetables can be attributed to the phytochemicals in plant foods. The word phytochemical simply refers to compounds found in plants. Studies show that many phythochemicals have amazing nutritional powers, and more are being discovered all the time.
The term given to the nutritious compounds in plants is phytonutrient. Plant foods are probably best known for their high levels of vitamins, minerals and fiber. However, there are other types of phytonutrients as well. Many plants also contain healthy fats and protein, for example. In addition, recent research has uncovered hundreds of other disease-fighting phytochemicals in plants that do not fall into traditional dietary categories.
Among the most studied nutrients in plant foods are antioxidants. These are vitamins and other compounds that inhibit oxidation, a process that all cells of the body undergo every day. Oxidation damages cells, and it is strongly linked to the development of cancer, heart disease and other illnesses. Oxidative stress, the stress that cells undergo during the process of oxidation, is caused by molecules known as free radicals.
Antioxidants include vitamins like A, C and E as well as a host of other compounds. Some of the more powerful phytonutrients that are unique to plants are organo-sulfurs, terpenoids, flavonoids, isoflavonoids, lignins and organic acids. These compounds protect plants from environmental damage, and it turns out that they are protective to humans as well. These substances also give plants their rich colors and flavors.
Another important group of phytochemicals are the phenols, which include the anthocyanidins that give blueberries and grapes their dark blue and purple colors. Flavonoids and isoflavones are also phenols; these compounds are noteworthy for their apparent ability to protect the body from hormone-related cancers like breast and prostate cancer. The organosulfur compounds in vegetables like broccoli, onions and garlic have a strong ability to rid the body of toxins, such as those found in pesticides and other environmental chemicals.
FRESH VERSUS FROZEN PRODUCE
An Often Underrated Nutritional Star
Researchers have found that the antioxidants in blueberries protect the entire body from an array of problems. For example, consuming blueberries can reduce muscle damage after strenuous exercise and can protect the nervous system from damage as well. Blueberries help to regulate blood sugar and strengthen the cardiovascular system, and they may also lower the risk of certain kinds of cancer, particularly colon cancer and other digestive system cancers. In addition, anthocynidins have been found to be especially effective in protecting the collagen in joints and capillaries from free radical damage. This means that blueberries have the power to reduce swelling (edema) and improve the condition of varicose veins and hemorrhoids, and they may also help to prevent hardening of the arteries and arthritis.
Studies have shown that people who consume a cup or two of blueberries per day can lower total cholesterol and triglyceride levels in the blood as well as raise levels of HDL (good) cholesterol. Another benefit of blueberries in relation to heart health is their apparent ability to increase the activity of an enzyme known as eNOS (endogenous nitric oxide synthase). When eNOS activity increases, the function of the cardiovascular system improves. And finally, blueberries appear to contain compounds that can lower blood pressure.
Blueberries are also good for the brain. A promising study of older adults showed that those who ate blueberries regularly scored better on memory tests. Researchers believe that this may be due to the fact that the antioxidants in blueberries can prevent nerve cell damage, allowing nerves to send information to the brain more smoothly as a person ages. In addition, the antioxidants in blueberries seem to be highly protective of the retina of the eyes, which are especially vulnerable to oxidative damage.
Choosing and Storing Blueberries
Crucifers Cut Cancer Risk
Another of broccoli’s weapons against cancer is sulforaphane, which removes toxins from the digestive system that may cause colon and other cancers. Broccoli also contains indole-3-carbinol, which supports the metabolism of estrogen and converts it into a form that is said to inhibit cancer growth and decrease breast cancer risk.
Other Health Benefits of Broccoli
Broccoli also contains flavonoids, the same powerful antioxidants found in blueberries. In addition, compounds in broccoli have the ability to deactivate acetylcholinesterase, an enzyme that prevents the breakdown of a neurotransmitter that is critical to memory. So eating broccoli may help to preserve and even improve memory.
Choosing and Storing Broccoli
Though there are more than a thousand varieties of potatoes, they are classified into several types according to their skin color. Types include russet, yellow, red, white, blue/purple and sweet potatoes. Of these, sweet potatoes top the list in terms of nutritional value. However, all potatoes have a place on the list of super foods.
Red, Russet and Blue Potatoes
White and Yellow Potatoes
Choosing and Storing Potatoes
Though avocados are relatively high in fat, the fat is mostly in the form of omega 3, an essential fat that has received much attention because it is so vital to optimal health. A one-cup serving of avocado contains 160 milligrams of alpha-linolenic (omega 3) acid. In one study, consuming omega 3 fats lowered levels of LDL cholesterol and triglycerides by 22 percent and raised HDL cholesterol by 11%. This suggests that avocados are an excellent food for people looking to improve cardiovascular health.
While the protein and omega 3 fats in avocados alone are enough to earn them superfood status, they also contain carotenoids that can protect the body from oxidative stress. While carotenoids are usually found in orange and red fruits and vegetables, the dark green avocado contains an impressive array of these nutrients as well. The carotenoids in avocados include alpha-carotene, beta-carotene, beta-cryptoxanthin, lutein, zeaxanthin and others. Carotenes are fat-soluble, and it turns out that the avocado has just the right combination of fats and phytonutrients for maximum absorption in the body. A one cup serving of avocado can increase carotenoid absorption two to fourfold.
The avocado’s combination of nutrients also includes the minerals selenium and zinc as well as phytosterols. In combination with antioxidant vitamins and omega 3 fats, these compounds make avocados strongly anti-inflammatory. It is widely believed that reducing or preventing inflammation is one of the most important ways to protect the body from a host of problems, from heart disease and cancer to arthritis and Alzheimer’s disease. Avocados are also more densely packed with blood pressure-lowering potassium than bananas.
Another major benefit of avocados is that they are very low in carbohydrates but still high in fiber, making them an excellent food for people with diabetes, prediabetes and insulin resistance. A single avocado contains more than half the daily recommendation of fiber.
There is also 40 percent of the daily folate recommendation in a single avocado, and the fruit is a good source of vitamin E as well. Research shows that people whose diets are higher in vitamin E may have a 30-40% lower risk of coronary artery disease. Folate, one of the B-complex vitamins, helps to protect the brain from the effects of aging and may help to ward off depression. It is also necessary for the development of red blood cells and for cardiovascular health.
The garlic plant can be cultivated year round in mild climates. The hard-necked variety is cultivated in cooler climates, while soft-necked garlic is usually grown closer to the equator. Though it is grown in many regions, China is by far the world’s largest producer of garlic, contributing 77% of the world’s garlic crop each year.
Garlic’s Fascinating History
The Healing Powers of Garlic
Garlic also contains a generous helping of antioxidant vitamins that rid the body of toxins and may help to prevent cancer. In addition, garlic can help balance blood sugar, detoxify the liver and improve the circulation of blood. It is also thought that garlic has a positive effect on the function of the nervous system.
Research has also shown that garlic can be used to treat not only bacterial infections, but also fungal infections and viruses. In fact, it has a powerful overall effect on the immune system due mostly to allicin and other antioxidant compounds. Few vegetables have such a wide variety of health benefits.
Choosing and Storing Garlic
Throughout the world, spinach has been considered one of the most nutritious of the leafy greens for centuries. The plant grows well in temperate climates with the United States and the Netherlands being two of the world’s largest spinach growers. Spinach is usually available in three varieties: baby spinach, Savoy and smooth-leaf. Baby spinach leaves are small and tender, while the leaves of Savoy spinach are curly with a springy texture. Smooth-leaf spinach is flat with a texture similar to Savoy.
The ability of the antioxidants in spinach to reduce the effects of oxidative stress has been demonstrated in studies that show an inverse relationship between spinach consumption and the risk of artherosclerosis and high blood pressure. The green’s blood pressure lowering effect may be due not only to the antioxidants in the vegetable but also to the presence of protein components known as peptides. Peptides inhibit the action of an enzyme called angiotensin that is associated with high blood pressure.
Spinach has a high concentration of the carotenoids lutein and zeaxanthin, which are highly effective in reducing the consequences of oxidative stress on the retina and macula of the eye. Research suggests that regular spinach consumption can help reduce the risk of eye problems like macular degeneration that are associated with aging.
There are also more than a dozen anti-inflammatory, cancer-fighting flavonoids in spinach. Flavonoid extracts from spinach have been shown to slow the growth of stomach cancer in humans and skin cancer in laboratory animals. In addition, a study of women in New England showed that the more spinach a woman ate, the less likely she was to contract breast cancer. The flavonoids and carotenoids in spinach also appear to be able to reduce inflammation of the digestive tract.
Other notable phytonutrients in spinach are glycoglycerolipids, fat-related molecules needed for the process of photosynthesis. Along with flavonoids and carotenoids, these compounds have been shown to protect the digestive tract from the effects of inflammation. In addition, a promising study on the relationship of spinach intake and prostate cancer showed that consuming spinach was greatly associated with a decreased risk of aggressive prostate cancer.
Another highly concentrated nutrient in spinach is vitamin K. A half cup serving of cooked spinach provides five times the daily recommended amount of this vitamin. Vitamin K is necessary for blood clots to form, so it can help prevent hemorrhaging. It also helps to prevent the breakdown of bone and works along with the calcium and magnesium in spinach to promote bone health and strength.
Choosing and Storing Spinach
SOYBEANS AND OTHER LEGUMES
Other powerful phytonutrients in soybeans include folate, vitamin K, calcium, magnesium and iron. The beans also contain disease-fighting phenolic acids, phytoalexins, phytosterols, peptides and saponins. Saponins from soy have been studied for their effect on cardiovascular health. Animal studies suggest that this compound can help the body move cholesterol through the GI tract before it can accumulate in the blood. In other words, soy may help to lower cholesterol levels.
Though research is inconclusive, many nutritionists believe that soy may also be beneficial to women who suffer from hot flashes during menopause. It has often been noted that in Asia, where soy is a staple of women’s diets, only a small percentage (10-20%) of women report experiencing hot flashes during menopause. In contrast, 70-80% of women who eat Western diets say they experience hot flashes in the menopausal years.
Other Noteworthy Legumes
Choosing and Storing Legumes
The Antioxidant Vegetable
The orange pigment in pumpkin comes from the cartenoids it contains. Pumpkin is rich in beta- and alpha- carotene as well as beta-cryptoxanthin, which may be an even more powerful antioxidant than the carotenoids. Laboratory research suggests that the alpha-carotene in pumpkins may have the power to inhibit the growth of cancer cells. Beta-cryptoxanthin appears to reduce the risk of developing lung cancer and arthritis. Pumpkin also contains lutein and zeaxanthin, which can help protect the eye from damage caused by UV light, lowering the risk for cataracts and age-related vision loss.
Other phytochemicals in pumpkins seem to have remarkable anti-inflammatory capabilities and have been widely studied for their effect on specific molecules, enzymes and cell receptors that are associated with inflammation. While low in fat, pumpkin is also a reasonable source of alpha-linolenic acid, an anti-inflammatory omega 3 fatty acid. Because of the anti-inflammatory and antioxidant benefits of pumpkin, this vegetable has attracted much attention in the area of cancer research. The anti-inflammatory compounds in pumpkins also appear to have anti-bacterial and anti-viral effects.
Not only is the flesh of a pumpkin highly nutritious, but its seeds and oil are remarkably healthy as well. Pumpkin seeds contain vitamin E, iron, magnesium, potassium and zinc as well as essential fatty acids. The high zinc content of pumpkin seeds and pumpkin seed oil may help to protect men from prostate cancer. In addition to being anti-inflammatory, the vitamin E and plant sterols in pumpkin seed oil can boost the immune system, balance hormones and lower cholesterol levels.
Choosing and Storing Pumpkins
A Smorgasbord of Phytonutrients
Tomatoes are an excellent source of antioxidant vitamins C and A, as well as vitamin K, which is essential to bone health and the ability of blood to clot. In addition, the potassium, magnesium, niacin and vitamin E in tomatoes protect the heart. Research has repeatedly shown that tomato consumption can improve heart health in two ways. First, tomatoes are an incredibly rich source of antioxidants and second, they help to regulate fats in the bloodstream and reduce cholesterol levels. Also, the lycopene in tomatoes helps lower the risk of lipid peroxidation, a process through which fats in the bloodstream or cell linings are damaged by oxygen. When fats are damaged in this way, inflammation occurs and the immune system is aggravated, causing deterioration of the cardiovascular system over time. Compounds in tomatoes also help to prevent platelets in the blood from clumping together and forming dangerous clots that can cause heart attacks and strokes.
Tomato consumption may also help to protect bones. In one study of the effects of lycopene on bone health, tomatoes and other foods rich in lycopene were removed from the diets of postmenopausal women for four weeks. The result was an apparent increase in signs of oxidative stress in the bones of these women.
Choosing and Storing Tomatoes
Free Radical Scavengers
Pomegranate is also a rich source of potassium, another nutrient that is vital to heart health because of its ability to help lower blood pressure. A study of people with hypertension revealed that those who drank pomegranate juice for two weeks were able to lower their blood pressure significantly. The researchers believe that this is because pomegranate can inhibit the action of antiotensin-converting enzyme, which raises blood pressure.
Another possible benefit of pomegranate juice is that it appears to have anti-viral and anti-bacterial effects. Ellagitannins, a group of especially powerful antioxidant phytochemicals in pomegranate are being studied in a number of clinical trials, and scientists believe that it may be capable of helping to fight a range of health conditions. The trials are designed to determine whether pomegranate juice or extracts from pomegranate can be used to treat diseases like prostate cancer, lymphoma, diabetes, viral infections and artherosclerosis.
Choosing and Storing Pomegranates