Most of us aren’t getting the nutrients we think we are. A comparison between the 2013 International Food Information Council (IFIC) Functional Foods Consumer Survey and National Health and Nutrition Examination Survey (NHANES) data exposed large gaps in the percentage of consumers who believe they are getting the recommended Dietary Reference Intakes (DRI) and the percentage of those who actually do. 68% believed they consumed enough vitamin D, but only 32% actually did. For potassium, 61% believed they consumed enough versus the less than 3% that actually did; for fiber, it was 67% versus 5%.
So why aren’t we giving our bodies the essential nutrients we need? Poor dietary choices are the biggest factor. But another part of the problem is our modern food system. Even when we make the right food choices, the food we consume today may have lower nutrient content than what our grandparents ate.
The Composition of Foods reference manual shows that during a 51-year period potatoes lost 45% of their iron and 35% of their calcium; broccoli dropped 80% in copper and 75% in calcium; and tomatoes lost 90% of their copper. One study, published in the Dec 2004 issue of the Journal of the American College of Nutrition, looked at U.S. Department of Agriculture data on nutritional content of 43 vegetables and fruits from 1950 and 1999 and found declines in protein, calcium, phosphorus, iron, riboflavin and vitamin C. There could have been declines in other nutrients as well, but they were not studied in 1950. Another study, in the British Food Journal, looked at 20 vegetable crops from 1930 to 1980 and found that the average calcium content declined 19%, iron 22%, and potassium 14%.
4 possible factors contributing to lower nutrient levels in our food:
1. Environmental Dilution Effect/Fertilizing for Higher Yields (other environmental factors are irrigation, climate, soil)
With the growing world population and changing agricultural economy, farmers feel pressure to increase crop yields on less land. Fertilization and irrigation are two of the environmental means used to do so. Since the 1940s, scientists have observed a decrease in the concentrations of minerals in plants with the increase in crop yields. This is known as the “dilution effect.”
One example of the dilution effect is a study of red raspberry plants grown in three different conditions: (1) in soil with 12 ppm of phosphorus and no fertilizer, (2) in the same soil, but fertilized with 22 ppm of phosphorus, and (3) in the same soil, but fertilized with 44 ppm of phosphorus. Eight months later, the plants fertilized with 44 ppm of phosphorus contained an approximately 20% higher concentration of phosphorus than the unfertilized plants, but the concentrations of the other eight minerals measured declined by 20-55%. (Measured minerals included nitrogen, potassium, calcium, magnesium, manganese, copper, boron and zinc.)
2. Genetic Dilution Effect/Breeding and Genetically Modifying Plants for Higher Yields
Breeders have cultivated crop varieties to produce higher yields through breeding and genetic modification. Some studies suggest that optimum crop yields do not equal optimum nutritional content. These studies compare nutrient content of several varieties of a single food grown side by side (this way the environmental variables like soil, fertilization, irrigation, pest control, climate, harvest, etc. are all constant).
One study measured calcium and magnesium concentrations in 27 different commercial broccoli hybrids grown in 1996 and 1997 in South Carolina. It found a negative correlation between yield and concentrations of calcium and magnesium; meaning as yields increased, calcium and magnesium concentrations decreased. The authors suggested that the broccoli hybrids with denser heads had grown larger without accumulating more calcium and magnesium in the same proportion, creating a dilution effect.
Another study on wheat also found negative correlations between yield and mineral concentrations. The average rate of decline of six minerals was 0.20% to 0.33% per year or 22% to 39% declines over a 100-year period. So, again, with varieties bred for higher yields, nutrient concentrations may not remain constant and thus become diluted.
3. Soil Depletion
Soil isn’t just dirt. It’s made up of mineral matter, water, air, and organic matter and is home to bacteria, fungi, actinomycetes, algae and protozoa. These microorganisms don’t just live there, but also play roles in the changes occurring in the soil and affecting plant nutrition, in both beneficial and harmful ways. Soil can have different textures (depending on the combination of sand, silt and clay), structures, colors and acidity. These are just a few of the factors to consider when looking at soil fertility. Soil nutrition is the foundation of plant nutrition, which is why farmers supplement their soils with nutrients like nitrogen, potassium, phosphorus, zinc and boron.
However, the focus has largely been on the size and growth rate of crops as opposed to nutrient content of the product. Modern agricultural practices (such as monoculture farming) could be stripping the soil of its nutrients faster than they can be replenished. It was presented at the Rio Earth Summit in 1992 that in the past 100 years mineral content of agricultural soils in the U.S. had been depleted by 85%. And this hadn’t just happened in the U.S., but all over the world. Soils in Africa had 74% less minerals; Asia, 76% less; Europe, 72% less; South America, 76% less; and Canada, 85% less minerals than 100 years ago.
4. Picked Before Its Prime
Produce destined for far away locations is often picked before it is ripe so that it can make the long journey and still have time on the shelves or in the produce bins. This means the produce has less time to absorb and accumulate nutrients. Take potatoes, for example. Freshly dug they contain 21 mg of vitamin C per 100 g, but this falls to 9mg per 100g after three months of storage, and then to 7 mg after nine months of storage.
A Note from Dr. Carl:
Nutrient depletion in our food can be a politically charged topic. With many mixed and conflicting messages, it can be difficult to know the truth in some cases. Studies on more foods, nutrients, and phytochemicals are needed to assess how widespread or specific the dilution effects may be. Growers should focus on macro and micro nutrient content, as well as yield. Fresh fruits and vegetables are still our best sources for nutrients — they just may not be giving us as much as they once did. The safe bet is to eat as much fresh food as you can, as well as to supplement to cover any micronutrient gaps in your diet.
That’s where Reliv nutritional products come in. Our science-backed formulas deliver optimal nutrition to give your body whatever it’s not getting through diet alone. Think of it as your nutritional health insurance policy.
To your health,
Dr. Carl W. Hastings
Vice Chairman and Chief Scientific Officer
Thank you Reliv for another great article!
This statement has not been evaluated by the FDA. Reliv products are not intended to diagnose, treat, cure, or prevent any disease.
Changes in USDA food composition data for 43 garden crops, 1950 to 1999
“IFIC Fuctional Foods Survey Shows Nutrient Shorfalls”, Nutraceuticals World, Nov 2013
Declining Fruit and Vegetable Nutrient Composition: What Is the Evidence?
Human Health, the Nutritional Quality of Harvested Food and Sustainable Farming Systemshttp://www.nutritionsecurity.org/PDF/NSI_White%20Paper_Web.pdf