For decades, the emphasis was on an adequate diet; the minimal amount of protein, minerals, vitamins, calories and fats needed to get you through the day. Meat, with its high levels of protein and energy, took pride of place on the table and vegetables and fruits were relegated to supporting roles.
Today we know that what we eat influences our health over time and so science is interested in what is the best diet for maintaining health through all the stages of life. It turns out that antioxidants in ordinary vegetables and fruit, which were not considered essential for an adequate diet, are an important part of optimal health. Their effect on our long-term health is cumulative, helping to protects us from the ravages of time and our own metabolism. One of the most undervalued aspects of whole foods in this regard, are the benefits of an alkaline diet.
Any food in its raw, unrefined form. This includes all the unprocessed grains, fruits, beans, vegetables and meats. Whole foods are very complex by nature and we are learning more about the interactions among foods and their constituents, such as fibre, nutrients, and phytonutrients that strengthen their health-promoting abilities. We refer to this as “food synergy.”
We also know there are many components in foods yet to be identified that we will need to learn about. Consumption of fruits, vegetables, whole grains, nuts, legumes, and other plant-based foods should be the primary dietary approach to disease prevention, rather than individual nutrient or food components.
Antioxidants work by neutralizing highly reactive, destructive compounds called free radicals. Free radical production is actually a normal part of life, part of the equation of simply breathing in oxygen. Usually, the body's natural defence systems neutralize free radicals that develop, rendering them harmless. However, environmental assaults on the body, such as UV-radiation, pollutants and alcohol, can overpower the body's ability to neutralize free radicals, allowing them to cause damage to the structure and function of the body's cells. There is good evidence that this damage contributes to aging and leads to a host of illnesses, including cancer and heart disease.
Antioxidant defences against this damage include ascorbate (Vitamin C), tocopherol (Vitamin E) and carotenoids, just to name a few. Fruits and vegetables are the principal source of ascorbate and carotenoids and are one source of tocopherol. Plants have developed thousands of kinds of antioxidants to protect themselves from specific threats to their own health and so there is no single antioxidant that will protect us from the many types of free radicals that are generated throughout the body. That's why it's important to eat a wide variety of fruit and vegetables and, because their efficacy is short-lived, to eat them often. In fact, eating several different kinds of vegetables or fruits at the same time, such as in a salad, creates a synergy that enhances the antioxidant benefit.
According to the World Health Organization, it has been projected that, by 2020, chronic diseases will account for almost three-quarters of all deaths worldwide, and that 71% of deaths due to ischemic heart disease, 75% of deaths due to stroke, and 70% of deaths due to diabetes will occur in developing countries. The number of people in the developing world with diabetes will increase by more than 2.5-fold, from 84 million in 1995 to 228 million in 2025. On a global basis, 60% of the burden of chronic diseases will occur in developing countries.
Low dietary intake of fruits and vegetables doubles the risk of most types of cancer as compared to high intake and also markedly increases the risk of heart disease and cataracts.
Consuming more antioxidants helps provide the body with tools to neutralize harmful free radicals. It's estimated that there are more than 4,000 compounds in foods that act as antioxidants. The most studied include vitamins C and E, beta-carotene and the mineral selenium.
Many people think "supplements" when they think about getting more antioxidants. The supplement aisle, however, is not the only place to find these important compounds. Better places include the raw fruit and vegetable section of your supermarket. Why? Because the foods in these sections come packaged with other complementary nutrients and phytochemicals. They can provide better insurance than supplements that you're getting the antioxidants you need in the right amount and form. Here are some good food sources of the four most studied antioxidants.
Vitamin C: Also called ascorbic acid, vitamin C is a water-soluble vitamin found in all body fluids, so it may be one of our first lines of defence. This powerful antioxidant cannot be stored by the body, so it's important to get some regularly...not a difficult task if you eat fruits and vegetables. Important sources include citrus fruits, green peppers, broccoli, green leafy vegetables, strawberries, raw cabbage and potatoes.
Vitamin E: A fat-soluble vitamin that can be stored with fat in the liver and other tissues, vitamin E is promoted for a range of purposes from delaying aging to healing sunburn. While it's not a miracle worker, it's another powerful antioxidant. Important sources include wheat germ, nuts, seeds, whole grains, green leafy vegetables, vegetable oil and fish-liver oil.
Beta-carotene: The most studied of more than 600 different carotenoids that have been discovered, beta-carotene protects dark green, yellow and orange vegetables and fruits from solar radiation damage. It is thought that it plays a similar role in the body. Carrots, squash, broccoli, sweet potatoes, tomatoes, kale, collards, cantaloupe, peaches and apricots are particularly rich sources of beta-carotene.
Selenium: This mineral is thought to help fight cell damage by oxygen-derived compounds and thus may help protect against cancer. It is best to get selenium through foods, as large doses of the supplement form can be toxic. Good food sources include fish, shellfish, red meat, grains, eggs, chicken and garlic. Vegetables can also be a good source if grown in selenium-rich soils.
In Australia the National Health and Medical Research Council (NHMRC) guidelines recommend that adults eat at least five kinds of vegetable and two kinds of fruit every day. Whenever possible, buy organic produce and avoid highly processed foods. While deeply coloured foods typically have high levels of antioxidants, they are also present in foods that are not highly pigmented. Herbs, spices and vegetables from the onion family are examples. If edible, eat the peels of organic fruit, such as apples, which often contain high quantities of antioxidants. Ripe fruits, in particular berries, contain higher quantities of antioxidants than fruits that are not ripe. Again, follow your taste buds to choose foods highest in antioxidants.
Although raw and whole is usually best, some antioxidants actually increase in potency when cooked for extended periods of time. These include the lycopene found in tomatoes and beta carotene in carrots and winter squash.
Do not underestimate the value of green leafy vegetables. Dark green leafy vegetables are good sources of many vitamins and minerals your body needs to stay healthy, like vitamin A, vitamin C, and calcium. They are also great sources of fibre. The darker the leaves, the more nutrients the vegetable usually has.
Dairy products are not the ideal food for bone health. 100 g of a low oxalate high calcium green leafy vegetable such as kale, turnip greens or spring greens will have at least as much beneficial effect on calcium balance as 200g of milk. Using the green stuff instead of the white stuff also avoids the adverse effects of dairy fat on cardiovascular health.
Dark green leafy vegetables will protect and strengthen bone by raising blood pH and providing vitamin K and vitamin C. They are a good source of plant carotenes, which meet the body's needs for vitamin A safely and naturally. Green leafy vegetables are also high in folate, which is highly beneficial to general health. It is hard to imagine a food more supportive of bone health than kale or spring greens. NOTE: Some vegetables such as spinach, purslane and rhubarb are high in oxalate, which hinders absorption of their calcium.
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