Many Americans’ diets are deficient in seven key nutrients. The reasons? Industrial agriculture’s push for high yields at the expense of nutrient density, plus a food industry conspiring to addict us to processed junk.
Diets heavy in processed foods have left Americans overfed yet undernourished.
Photo By iStockphoto/fstop123
It’s a paradox of modern culture: Though more than a third of us are classified as overweight or obese, and though more than 3,700 calories of food are available daily for every person in the United States, many of us still don’t get enough of some essential nutrients, including potassium, calcium and vitamin D. This paradox, in which we are overfed and undernourished, is sometimes called nutrient deficiency.
In its latest update of the Dietary Guidelines for Americans (2010), the United States Department of Agriculture (USDA) announced that our average intake of some of these “nutrients of concern” is so low as to be a widespread public health issue. How is it that we eat so much, yet lack key nutrients?
The answer to that question is complex, encompassing everything from food distribution to the failings of industrial agriculture. One thing is clear: We now eat too much of the wrong kinds of food. We consume too many sugary soft drinks and fat-laden desserts and not enough nutrient-dense fruits and vegetables, beans, and whole grains. As our waistlines expand, diet-related diseases and their associated costs grow along with them. Science has linked nutrient deficiencies to a variety of diseases and unhealthful conditions. For example, a recent study in Australia that compared five types of diets found a direct link between women who preferred nutrient-poor foods and increased osteoporosis and fractures, which indicates calcium deficiencies. Few consume the recommended daily amount of potassium — a nutrient that helps lower blood pressure — and one in three of us suffers from hypertension.
Increasing evidence shows that our consumption of fats, sugars and fluffy white foods contributes to the incidence of degenerative, age-related diseases such as cancer, cognitive decline, cardiovascular disease and stroke. Biochemist Bruce Ames — who has won numerous prestigious awards, including the National Medal of Science — argues that widespread vitamin and mineral deficiencies in modern diets result in chromosomal damage that leads to cancer and accelerated aging.
Some of the harm from nutrient-poor diets can occur in the earliest stages of human development. A major new study published in the Journal of the American Medical Association found that mothers who took a supplement of folic acid (the more stable, supplement form of folate) were 40 percent less likely to have a child later diagnosed with autism. A key finding in this study of more than 85,000 mothers was that the supplement has to be taken prior to conception. Folate contributes to prenatal brain and spinal development, and most of that development occurs during the first 28 days of pregnancy — before most women know they’re pregnant. So the researchers determined that women should begin taking folate even before becoming pregnant.
If the solution to these problems seems obvious — eat more fruits and vegetables — why is it so difficult to achieve? According to pediatrician and former FDA commissioner David Kessler, author of The End of Overeating, we have been trained to prefer foods high in sugar and fat. Eating and the desire to eat release dopamine, a brain chemical associated with “reward” feelings, Kessler writes. He cites a study in which people tracked the food they ate and rated it for pleasure. They gave the highest ratings to foods high in fat and sugar. Unsurprisingly, they also ate more of them, consuming 44 percent more of the pleasure foods. Because we prefer foods high in fat and sugar, our spending on processed foods and sweets has nearly doubled — from 11.6 percent of our grocery budgets in 1982 to 22.9 percent in 2012 (see “We’re Spending Less on Meat, But Way More on Junk” in the Image Gallery).
Unlike most evolutionary processes, this shift to an overwhelming preference for sugars and fats didn’t occur over a span of centuries or millennia. We went from relying upon staples, such as meat, eggs, dairy products, and fruits and vegetables, to processed foods — often called “convenience” foods — in just a few decades. After World War II, the food industry kicked into full gear, and high profit margins and convenience (including shelf life) took precedence over nutrition and flavor. The industry was unrelenting. Advertising and the media, along with the advent of supermarkets and advances in packaging, caused convenience foods to win over old-fashioned basics. Today, the average person “eats 33 pounds of cheese — triple what we ate in 1970 — and 70 pounds of sugar — about 22 teaspoons a day,” writes New York Times reporter Michael Moss in Salt Sugar Fat: How the Food Giants Hooked Us. He continues: “We ingest 8,500 milligrams of salt a day, double the recommended amount, and almost none of that comes from the shakers on our table. It comes from processed food.” Salt often covers off flavors and it acts as a preservative.
Our nation’s farm policies have helped the food industry addict us. “Agricultural subsidies have helped bring us high-fructose corn syrup, factory farming, fast food, a two-soda-a-day habit and its accompanying obesity, the near-demise of family farms, monoculture and a host of other ills,” writes New York Times columnist Mark Bittman.
The latest USDA analysis of the average shopping cart found that most U.S. citizens spend far less on fruits and vegetables than they do on refined breads, pastas, cereals and cookies, and frozen desserts and pizzas. Similarly, the National Health and Nutrition Survey found that the average consumption of dark green vegetables and whole grains falls well below suggested levels, each now at less than 10 percent of the totals recommended. Meanwhile, potato chips are the top source of oils in our diet, and carbonated beverages account for more than a third of added sugars. (For more on the top sources of calories in our diet, see “Top 20 Sources of Calories in the Average U.S. Diet.”)
Ironically, the industrialization of our food supply has meant that even those who opt for healthy choices get less nutrition for their food dollar than our ancestors did. Many modern foods contain significantly fewer nutrients than they did a century ago. According to Donald Davis, a retired chemist from the University of Texas, many studies have shown that fertilizers, irrigation and other inputs — applied in the pursuit of higher crop yields — have led to diluted protein, vitamins and minerals in many crops.
Davis also points out that plant breeders, focusing strictly on increasing yield, have actually given us higher-yielding varieties that are less nutrient-dense. His 2004 study, “Changes in USDA Food Composition Data for 43 Garden Crops, 1950 to 1999,” showed the average nutrient decline in fruits and vegetables was about 15 percent. Protein content in wheat and barley declined 30 to 50 percent since the 1930s.
We’ve reported many times on the increased omega-3 fatty acids in eggs from pasture-raised hens, and on the many studies that have shown organic foods contain higher levels of vitamin C and some antioxidants.
A recent study by researchers at Clemson University, published in the Journal of Animal Science, found that meat from steers finished on pasture contained less saturated fat, 54 percent more B vitamins and beta carotene, and a whopping 117 percent more conjugated linoleic acid, an essential fatty acid and antioxidant linked to improved immune function.
Though the reasons for dwindling nutrition in our food supply are convoluted, the solution is simple: Eat organic; eat more whole foods and fewer processed foods; and eat meat, eggs and dairy products from pasture-based — rather than industrial — systems. Heirloom vegetable varieties may also be more nutritious than modern hybrids. If you are what you eat, why be cheap, fast and empty of value?
According to the Dietary Guidelines for Americans, many of us don’t get enough of the following vital nutrients in our diet.
Why you need it: Calcium builds strong bones and prevents osteoporosis. It plays a vital role in nerve transmission and cardiovascular health, and works with vitamin D to maximize each nutrient’s absorption. You need 1,000 mg per day from ages 19 to 50. If you’re over 50, you need 1,200 mg.
Where to find it: The primary source of calcium is milk and dairy products. Milk contains 300 mg per cup, and yogurt has 332 mg per three-quarters cup. Plant sources include dark leafy greens — collards have 133 mg of calcium per half-cup. Fortified cereals and soy products also contain calcium, as does canned fish such as sardines.
Why you need it: A fiber-rich diet reduces the risk of heart disease, obesity and Type 2 diabetes. Fiber helps you feel full and stay satiated. It’s also important for gastrointestinal health. Men ages 19 to 50 need about 38 grams of fiber per day; men over 50 need 30 grams. Women ages 19 to 50 need 25 grams; women over 50 need 21 grams.
Where to find it: Cooked or canned beans contain 12 to 19 grams per cup. One half-cup of 100-percent bran cereal contains 12 grams. Oatmeal offers 4 grams per half-cup.
Why you need it: Especially important for women of child-bearing age, folate (or folic acid, which is the more stable form found in fortified foods and supplements) helps prevent birth defects. Daily requirements for folate vary from 300 to 600 micrograms (mcg), with women of childbearing age needing 300 mcg a day and pregnant women needing 600 mcg per day.
Where to find it: Food sources include lentils (358 mcg per cup) and dark leafy greens, such as cooked spinach (262 mcg per cup) and cooked collards (177 mcg per cup). Many breads are now fortified with folic acid. Women planning to become pregnant should ask their doctor about taking supplements.
Why you need it: The most widespread nutrient deficiency in the world, iron is essential to the formation of hemoglobin, which transports oxygen in red blood cells throughout the entire body. It also supports energy metabolism. Women ages 19 to 50 need 18 mg a day. Men and post-menopausal women need 8 mg a day.
Where to find it: Lean meats, poultry and seafood provide heme iron. Beef provides 4.5 to 7.0 mg per serving, while 3 ounces of clams provides 7.4 mg or more. Plant sources provide non-heme iron, which is less efficiently absorbed by the body. Beans and lentils (1.8 to 4.3 mg per half-cup) and spinach (4.5 to 7 mg per half-cup) are good sources, as are fortified cereals.
Why you need it: Potassium blunts the effect of eating too much salt. It maintains fluid balance and improves nerve impulses and muscle contractions, including those of the heart. Potassium helps prevent kidney stones and bone loss. You need 4,700 milligrams (mg) a day.
Where to find it: Potassium’s best sources are unprocessed fruits and vegetables as well as dairy products. Cut back on salt, too, so the potassium you eat can work in other ways. Eight ounces of orange juice contains nearly 500 mg; a banana contains about 450 mg; a cup of lima beans contains 1,000 mg; and a baked potato contains more than 600 mg. Other sources: salmon (more than 400 mg in 3 ounces), avocado (975 mg in 1 avocado) and dried apricots (755 mg in one half-cup).
Why you need it: Vitamin B12 makes healthy red blood cells and helps nerve transmission. Recommended Daily Allowance (RDA) varies from 400 nanograms for infants to 2.8 mcg a day for lactating women.
Where to find it: Animal products such as meat, eggs and dairy products. Pastured is best. Two very high sources are sardines (8.11 mcg per 3.2-ounce serving) and salmon (6.58 mcg per 4-ounce serving). Vegetarian sources include nutritional yeast and fortified foods such as soy milk and tofu.
Why you need it: Essential for bone health, vitamin D may prevent breast and colon cancer, research suggests. Historically, lack of this vitamin has caused rickets, although this condition rarely occurs in developed countries. Children need 600 International Units (IU) per day. Adults need 200 IU from ages 19 to 50, and 800 IU per day from age 50 on.
Where to find it: MOTHER EARTH NEWS tests found that eggs from pastured hens contain 4 to 6 times the amount of vitamin D of supermarket eggs. Vitamin D can also be found in certain fish, such as salmon, herring and mackerel. The body itself manufactures vitamin D in the skin upon exposure to sunlight. The capacity of the body to produce it, however, declines by as much as 75 percent as we age. Excellent sources are salmon (1,059 IU in 4 ounces), sardines (175 IU in 3.2 ounces) and fortified foods (milk, orange juice).
The leading source of calories in an average 2,152-calorie day is sugary, grain-based desserts such as cakes and cookies. These foods (calories in parentheses) make up much of the rest. Calories listed don’t total 2,152 because people do eat some fruits and vegetables, which aren’t calorie-dense enough to make the list. The chart shows our reliance on processed foods.
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