NUTRIENT DEPLETION IN OUR FOODS
The alarming fact is that foods―fruits, vegetables and grains―now being raised on millions of acres of land that no longer contain enough of certain needed nutrients, are starving us―no matter how much we eat of them.
~ U.S. Senate Document 264
Plants can’t make minerals, and without minerals vitamins don’t work. We are made of the stuff of the earth, it is not surprising that any depletion in the minerals and nutrient content of soils reflects an increase in nutritionally related diseases in both animal and human populations.
Researches released at the 1992 RIO Earth Summit confirm that mineral depletion of our global topsoil reserve is rampant. At the time, U.S. and Canadian agricultural soils had lost 85% of their mineral content. Asian and South American soils were down 76% while throughout Africa, Europe and Australia, soils were depleted by 74%, 72% and 55% respectively.
MODERN AGRICULTURE IMPOVERISHES SOILS
The earth’s arable soils are about 95% mineral content, once you remove the water and airspace. Soils buffer and filter water and airborne pollutants, store critical moisture and important minerals and micronutrients.
Soil erosion, contamination with industrial pollutants, and depletion of our limited mineral resources is everywhere. Nevertheless, modern agricultural practices continue to consume water, fuel and topsoil at unsustainable rates. In addition, both crops and livestock deplete our soils by removal of the minerals and nutrients contained in the produce sold. Soil degradation is one of the largest threats to the long-term environmental sustainability of our planet.
Impoverished Soils = Impoverished Crops
The depletion of the nutrient content of our soils, through unsustainable agricultural practices, results in the inevitable loss of nutrient value in our crops. Between 1963 and 2000, Collard greens showed a 62% loss of vitamin C, a 41% loss of vitamin A and a 29% loss of calcium. Potassium and magnesium were down 52% and 84% respectively. Cauliflower had lost almost one-half of its vitamin C, thiamine and riboflavin, and most of the calcium in commercial pineapples had disappeared. The story was the same for all 25 fruits and vegetables analyzed.
Similarly, a Canadian study found dramatic declines in the nutrient content of produce grown over a 50-year interval to 1999. During that time, the average Canadian spud lost 57% of its vitamin C and iron, 28% of its calcium, 50% of its riboflavin and 18% of its niacin. It is not surprising that you must eat eight oranges today to get the same amount of vitamin A your grandparents got from a single orange.
How Nutrients are Removed from Soils
Erosion of topsoil by wind and water is accelerated by over cultivating, overgrazing and destruction of natural ground cover. The loss of organic matter causes the soil becomes increasingly acidic, also results in a concurrent loss of nitrogen, minerals, and trace elements and reduces the ability of soil to hold moisture and support the growth of healthy plants.
High-yield crops place a further burden on limited nutritional capacity of our soils. For example, in 1930 an acre of land would yield about 50 bushels of corn. By 1960, yields had reached 200 bushels per acre which far beyond the capacity of the soil to sustain itself. The soil becomes too alkaline to sustain crop growth.
Over-use of NPK (nitrate, phosphate and potassium) fertilizers gradually reduces soil pH, rendering the soils too acidic to support beneficial bacteria and fungi. These symbiotic organisms assist the plant in absorbing nutrients from the soil. Moreover, NPK fertilizer has been found to bind soil-based selenium, making it unavailable for root absorption.
Over Use of Pesticides and Herbicides
The weakening of both our soils and crops through the practices of commercial agriculture creates an overwhelming dependence on the use of pesticides and herbicides to maintain crop yield. These extremely toxic organochlorine (OC) and organophosphorus (OP) kill our soils by slaughtering the symbiotic bacteria and fungi that promote nutrient uptake in plants. They also inactivate critical enzyme systems within the plant roots that are involved in mineral absorption, and they destroy the soil micro-organisms needed to create the organic-mineral complexes that naturally replenish the soil.
To make matters worse, these environmental poisons end up on our dinner table.
NUTRIENT DEPLETION THROUGH FOOD PREPARATION
Nutrient depletion of foods also occurs through the harvesting, storing and transport to markets that may be half a world away. Despite the dwindling nutrient content of foods by the time they reach the pantry, it is in the final preparation for the dinner table where considerably greater nutrient diminution occurs. The amount of this loss depends upon the way foods are prepared and the methods of cooking.
People may think boiling is the healthiest way of cooking. In fact, it generally associated with the greatest nutrient losses in both meats and vegetables. Boiling has been shown to reduce folic acid content by over 50% in spinach and 56% in broccoli. In another study, vitamin C losses from broccoli due to boiling exceeded 30%. And investigating the retention of several B-complex vitamins showed that boiling and deep-frying were the most aggressive of all cooking methods in depleting vitamin content. Rather than total immersion in water, it is better to boil food in a shallow layer of water. Also, rather than discarding the cooking juices, reclaim the micronutrients by using the liquid for the preparation of broths or gravies.
Most of studies report that steaming provides good retention of both vitamins and minerals in various food types. Recent studies confirm that steaming, microwaving and stir-frying for short duration are best to preserve the health promoting factors found in vegetables of the brassica family (broccoli, cauliflower and cabbage). Of all cooking methods, steaming appears to be one of the best for nutrient retention in vegetables. Both nutrient content and presentation are optimized when the vegetable is not immersed in the water and when exposure time is minimized.
While there has been controversy about the effects of microwaves on food quality and safety. Several studies report that cooking with microwaves allows foods to maintain more of the nutrient content because the vitamins and minerals are not leached out; microwaving preserves bioflavonoid content and B-complex vitamins. In one study, broccoli cooked by microwave was shown to preserve over 90% of its vitamin C and all of its health promoting sulforaphane content and concluded that microwave cooking, along with grilling and baking, was the preferred method to optimize nutritional value.
Similar to boiling, frying can cause significant destruction of overall antioxidant activity and nutrient loss of the health promoting glucosinolates and B-complex vitamins in vegetables. Also, deep frying has been found to incur severe denaturation of proteins in some vegetables. Meats in high temperatures (deep frying, pan frying and barbecuing) could lead to formation of harmful trans-fats, more importantly the Heterocyclic amines (HAs), which are genotoxic compounds can pose significant carcinogenic risk. Caution should be used if frying with margarine as opposed to better cooking oils, such as canola, soy and olive oil.
The conveniences of modern living incur many trade-offs when it comes to eating a healthy diet, most of us are simply unaware of our level of exposure to persistent environmental toxins and over-reliance on commercial, chemically based agriculture through the foods we place daily on our table. To start with, we can begin identify those foods most highly exposed to chemicals and stop treating vegetables, fruits as side dishes, understand that high quality of nutrition supplementation is our best defense against illness and disease.