Don’t ask the US federal government whether there are any health benefits to eating organic food. It won’t tell. No mere coincidence, then, that no pictures of farmers or farms (or fertilizers or pesticides) appear in the USDA food pyramid logo. The federal government encourages the consumption of more fruits, vegetables, and grains, but stops short of evaluating the farming systems that produce these same foods. An apple is an apple regardless of how it has been grown, the USDA food pyramid suggests, and the only take-home message is that we should all be eating more apples and less added sugars and fats.
But this message may be too simplistic. Over the past decade, scientists have begun conducting sophisticated comparisons of foods grown in organic and conventional farming systems. They’re finding that not all apples (or tomatoes, kiwis, or milk) are equal, especially when in comes to nutrient and pesticide levels. How farmers grow their crops affects, sometimes dramatically, not only how nutritious food is, but also how safe it is to eat. It may well be that a federal food policy that fails to acknowledge the connection between what happens on the farm and the healthfulness of foods is enough to make a nation sick.
Woodcuts by Mona Caron
In the late 1990s, researcher Anne-Marie Mayer looked at data gathered by the British government from the 1930s to the 1980s on the mineral contents of 20 raw fruits and vegetables. She found that levels of calcium, magnesium, copper, and sodium in vegetables, and of magnesium, iron, copper, and potassium in fruit had dropped significantly.
The 50-year period of Mayer’s study coincides with the post World War II escalation of synthetic nitrogen and pesticide use on farms. These agri-chemicals allowed farmers to bypass the methods of maintaining soil fertility by replenishing soil organic matter with cover crops, manure, and compost, and of controlling pests with crop rotation and inter-cropping. Reliance on chemical fertilizers and pesticides became a defining characteristic of conventional farming, while farmers who eschewed the use of agri-chemicals came to be considered organic.
In 2004, Donald R. Davis, a research associate with the Biochemical Institute at the University of Texas at Austin, published a similar analysis of data collected by the USDA in 1950 and again in 1999 on the levels of 13 nutrients in more than 40 food crops. Davis found that while seven nutrients showed no significant changes, protein declined by six percent; phosphorous, iron, and calcium declined between nine percent and 16 percent; ascorbic acid (a precursor of Vitamin C) declined 15 percent; and riboflavin declined 38 percent. Breeding for characteristics like yield, rapid growth, and storage life at the expense of taste and quality were likely contributing to the decline, Davis hypothesized. The “dilution effect,” whereby fertilization practices cause harvest weight and dry matter to increase more rapidly than nutrient accumulation can occur, probably also played a role, Davis suggested.
Meanwhile, researchers at the Rodale Institute in Pennsylvania were seeing a trade-off between use of synthetic fertilizers and food nutrient values in the Institute’s Farming System Trial.
“We looked at the major and minor nutrients of oat leaves and seeds, grown after 22 years of differentiation under conventional and organic systems,” says Paul Hepperly, research and training manager at the Institute. “We found a direct correlation between the increase of organic matter and the amount of individual minerals in the oat leaves and seeds. The increase in minerals ranged from about seven percent for potassium, up to 74 percent for boron. On average, it was between 20 and 25 percent for all the elements we looked at, and we looked at nitrogen, phosphorous, potassium, calcium, magnesium, sulfur, iron, manganese, copper, boron, and zinc. The production practices used on these oats was completely the same the year they were planted – the plots varied only by the legacy of what had happened to the soil as a result of the previous farming practices. This showed how dramatic the soil change had been and its effect on the nutrient content of the plant. We’ve done these tests not only on oats but also on wheat, corn, soybeans, tomatoes, peppers, and carrots, and we consistently find that the organic heritage improves soil and improves the mineral content of the food products.”
Probably due in part to a fertilizer effect, and partly because the use of chemical pesticides dampens the mobilization of a plant’s own defenses, conventionally grown whole foods also often have lower levels of antioxidants and other beneficial phytochemicals than the same foods grown organically.
Charles Benbrook, chief scientist at the Organic Center and former executive director of the Board on Agriculture of the National Academy of Sciences, maintains a database of all the studies published since 1980 that compare the nutrient levels of organic and conventional foods. His analysis of food comparison studies shows that, on average, conventionally grown fruits and vegetables have 30 percent fewer antioxidants than their organically grown counterparts. This makes enough of a difference, says Benbrook, that “consumption of organic produce will increase average daily antioxidant intake by about as much as an additional serving of most fruits and vegetables.”
The public health implications of farming methods that restore food nutrient density are tantalizing. Several studies released in 2007 suggest that moving US agriculture toward organic practices could help to reduce the incidence of some of our nation’s most debilitating and costly chronic diseases.
At the University of California at Davis, researchers compared organic and conventional tomatoes. They found that 10-year mean levels of quercetin were 79 percent higher in organic tomatoes than in conventional tomatoes, and levels of kaempferol were 97 percent higher. Quercetin and kaempferol are flavonoids, which epidemiological studies suggest offer protection from cardiovascular disease, cancer, and other age-related diseases.
A study led by Lukas Rist, head of research at the Paracelsus Hospital in Switzerland, demonstrated how farm practices affect health even several levels up the food chain. Rist analyzed milk samples from 312 breastfeeding mothers. He found that mothers consuming at least 90 percent of their dairy and meat from organic sources have 36 percent higher levels of rumenic acid in their breast milk than mothers eating conventional dairy and meat. Rumenic acid is one of a group of compounds that nutritional research suggests have anti-carcinogenic, anti-diabetic, and immune-modulating effects, and that favorably influence body fat composition.
Eager as we are to connect the dots between specific nutrients and specific health benefits, we’re still a long way from being able to understand or predict the effect of raising or lowering nutrient levels in one food or another. As Michael Pollan writes in his new book In Defense of Food, “Even the simplest food is a hopelessly complicated thing to analyze, a virtual wilderness of chemical compounds, many of which exist in intricate and dynamic relation to one another, and all of which together are in the process of changing from one state to another.”
Long-term human feeding trials are notoriously difficult to control, and, though epidemiological studies show a correlation between eating fruits and vegetables and decreased incidence of disease, these studies don’t identify which compounds in the food correspond with which health effects.
But even granting the many gaps in our knowledge of nutrient and health interactions, reducing the nutrient density of our whole foods seems a poor public health gamble. Americans already have trouble consuming the recommended daily amounts of fruits, vegetables, and whole grains. Diminishing the nutrient levels in the servings we do eat would seem to only compound our dietary problems.
Doctors don’t see many patients walk into their clinics with obvious deficiency-related illnesses like scurvy, says Dr. Alan Greene, attending physician at Stanford University’s Lucile Packard Children’s Hospital. But doctors are, he says, seeing a lot of suboptimal intake of nutrients. “For instance, a huge percentage of the population doesn’t get its recommended levels of calcium. Pregnant adult women should be getting 1,000 milligrams of calcium. By the time a healthy baby is born, the baby will have about 30,000 milligrams of calcium in its body, and all of that has to come from mom’s diet or mom’s body. The average mom is only getting about 700 milligrams a day during pregnancy, so that gap is mostly coming out of her bones, and is related to the osteoporosis we’re seeing later.”
Greene encourages patients to include fresh produce in their diets and to eat organic as much as possible. “I’ll talk about how fruits and vegetables are really important, and that when you choose organic you’re getting more of the great stuff, less of the bad stuff.”
Unfortunately (or fortunately for those of us who like to eat), we haven’t yet been able to design nutrient supplements that provide the same benefits as eating whole foods. “In all well-designed dietary intervention trials, where a carefully monitored amount of nutrients – vitamin C, vitamin E, antioxidants, etc. – were delivered to the animals or people in the form of fresh whole foods versus the same levels in the form of supplements, the animals or people who ate the whole foods universally responded better and were healthier,” says Benbrook of the Organic Center.
Ironically, less nutrient dense foods may be partly why we’re eating more and more. Phytochemicals contribute to the satisfaction we derive from foods. Some contribute to foods’ flavor profiles, while others, like resveratrol, help trigger satiety. It could even be that the second helping is an instinctive attempt to secure sufficient micronutrients.
“In cattle and animals, this is known as hay belly,” says Hepperly at the Rodale Institute. “If your hay gets rained on, you wind up with very low-quality hay because the water leaches out all the nutrients. You’ll see animals eating more of this hay than they normally would. They get these big bellies, and they’re unhealthy, but they’re just trying to get their nutrients. Ranchers know that if they have animals with hay belly, they have poor quality food. What we’ve done with the erosion of nutrient content in our foods – what we’ve done with additives, processing, and artificial production methods – is that we have basically produced a hay belly nation.”
The toxicity of many of the chemical pesticides used by conventional farmers is of little dispute. Indeed, the EPA’s pesticide registration process is based upon identifying a level of exposure that is acutely toxic to lab animals, then working backwards to identify an exposure level that the EPA feels poses an acceptable threat to human and environmental health.
As our understanding of the body’s biochemistry advances, however, EPA-sanctioned levels of pesticide exposure are becoming harder to swallow.
Caroline Cox is the research director for the Center for Environmental Health based in Oakland, California. One of her favorite examples of the complex interactions of pesticides comes from a study undertaken by Texas Tech University researchers.
“The researchers were looking at possible hormonal effects of the herbicide Roundup, and they looked at the production of male sex hormones,” Cox says. “Before a sex hormone can be made, cholesterol has to be carried by a special ‘dump-truck’ molecule from the blood vessel to the place in the cell where the hormone is synthesized. What the researchers found was that one of the ingredients in Roundup interferes with the production of that dump-truck carrier molecule. You’d have trouble dreaming up something so complicated. It’s no wonder that it has taken us decades to identify effects like that.”
Cox and other toxicology experts disagree that “the dose makes the poison,” the rationale underlying the EPA approach to regulating pesticides. It may be that there is no safe dose for many of the pesticides we are regularly exposed to.
“If you think of pesticide use starting right around World War II, since that time science has progressed and researchers have gotten more and more sophisticated in the kinds of science that they can do,” she says. “And what they are doing is identifying effects of pesticides at lower and lower exposure levels. For example, there are studies on amphibians that find effects from atrazine [used to control weeds in almost two-thirds of all US corn and sorghum acreage] at the tenth of a part per billion level, which is such a tiny amount that it is almost impossible to grasp just how small an amount that is. … What they found was this condition called intersex in the frogs, meaning that the frogs had both male and female sex organs.”
A glance at the data gathered for the USDA Pesticide Data Program reveals that even at breakfast we consume several servings of pesticides. In 2005, 88 percent of apples, 92 percent of milk samples, 52 percent of orange juice samples, 67 percent of wheat samples, and 75 percent of water samples were contaminated with pesticides ranging from herbicides to post-harvest fungicides. None of these pesticides we eat for breakfast gets a clean bill of health. The EPA lists some as probable carcinogens, and others as affecting reproductive and nervous systems.
Exactly how each of us tolerates daily low doses of pesticides will vary according to our genetic heritage, the other industrial toxins we’re exposed to, our health, and our age. The very youngest and oldest of us will probably suffer the most damage from pesticide exposure. “At particular moments of development, the immune and neurological systems of infants are profoundly vulnerable to exposure to chemicals,” says Benbrook at the Organic Center. “And in the case of the elderly, their livers don’t work as well at detoxifying chemicals as they did in the middle part of their lives.”
Logically, the more often we can eat food grown without pesticides, the fewer pesticides we’ll consume. The connection between food choices and pesticide consumption was demonstrated in a 2006 study led by Chensheng Lu of the Rollins School of Public Health at Emory University. Lu measured the metabolites of organophosphorus pesticides in children’s urine as the children alternated between eating conventional and organic diets for five days at a stretch. Results of the study showed that metabolites of two organophosphorus pesticides commonly used in agriculture decreased to nondetectable levels when the children’s diets were switched to organic and quickly escalated to detectable levels when the children returned to their normal conventional diets.
Daily doses of pesticides are particularly unappetizing given the existence of a highly productive model of farming that doesn’t need these toxic chemicals. “If you could give me a magic wand and I could make any changes that I want, I would have the EPA researching, developing, and helping farmers implement sustainable agricultural processes so they don’t need pesticides,” Cox says. “There are better ways to manage pests. Organic is a great example that it can be done.”
Cox’s wish hints at what official acknowledgement of the interaction between farming practices and the healthfulness of our food could mean. As a country, we’re stuck in the mode of regulating and mitigating the negative effects of conventional farming.
We could instead be spending our time and resources expanding and improving upon the organic model of food production and removing the structural barriers that limit regular access to organic food to a geographic and economic elite.
“Organic will be five to eight percent of the US food economy in the next couple of years,” says Bob Scowcroft, executive director of the Organic Farming Research Foundation (OFRF). “But to go from five percent to 40 is another story. That will involve policy work and institutional change.”
For starters, the nation’s agricultural colleges will need to develop the capacity to train more organic farmers. “Organic systems are more complex and biologically intricate compared to a conventional agri-chemical based production system,” says Hepperly of the Rodale Institute. “Right now, the official number of organic farmers is approaching 20,000 in the United States. If we were going to have 30 percent of US agriculture in organic, we’d have to have 200,000 organic farmers. We’re talking an enormous ramp-up in our education system.”
For that to happen, Congressional action is sorely needed to redirect the Farm Bill away from status quo conventional farming and toward farm and food healthfulness.
“Overall, the USDA has been spending about $2 billion per year on research, extension, education, economics and statistics. Less than one percent is specifically directed at the needs of organic production, processing, and marketing,” Mark Lipson of OFRF testified before the newly formed House Agriculture Subcommittee on Horticulture and Organic Agriculture in April 2007.
The list of structural barriers goes on. Because there isn’t good pricing data for organic crops, organic growers pay a five percent penalty surcharge on crop insurance. When organic growers incur an insured loss, they are repaid at conventional crop prices even though conventional prices are usually far lower than organic prices.
Many regions lack the distribution infrastructure even to supply organic farmers with compost. “Organic is highly geocentric,” says Steve Diver, who worked for 18 years for the National Sustainable Agriculture Information Service (ATTRA). “The organic infrastructure sucks to hell for most of the heartland of the country.” In California, Diver says, farmers can pick up the phone and order whatever soil amendments they need, in whatever quantities, from a local dealer who will deliver the goods right to the farm. But in many parts of the South, five to six farmers have to band together, order a 22-ton semi-truck load from out of state, then off-load the product into their own vehicles and truck it home.
Organic meat producers lack access to slaughterhouses. “You can’t sell meat unless it’s been slaughtered by USDA packing houses, and these slaughterhouses are mostly at CAFOs [concentrated animal feeding operations],” says Scowcroft. CAFO slaughterhouses generally won’t deal with the smaller numbers of animals that most organic meat producers are slaughtering at any one time. Even when they do, the CAFO slaughterhouse has to first be steam-cleaned and sterilized before animals can be slaughtered there for the meat to still qualify as certified organic. “And even then,” says Scowcroft, “there are a lot of chemicals used in the sterilization and the cleaning process, so what you really need are dedicated certified organic slaughter rooms.”
Try to get guidance from the federal government on the potential health benefits of eating organic, and you’ll find your questions quickly and politely deflected. The US Department of Health and Human Services will defer to its Food and Drug Administration (FDA). FDA spokespeople will say that “organic” is a term used by the USDA, not the FDA, and that the FDA has no policy on organics. The USDA will say that its mandate does not extend to passing judgment on the relative safety and nutritional benefits of organic versus conventional foods, and that the USDA’s task is simply to regulate use of the “certified organic” label.
With that passing of the apple, the federal government excuses itself from exploring whether conventional farming practices compromise the nutritional benefits of whole foods, and whether modern organic farming offers a model of food production that conveys significant health benefits. It’s anyone’s guess how many more studies will be needed before the relative merits of foods produced in different farming systems can become a topic of discussion among federal food and health officials. Agri-chemical companies led by Monsanto will certainly use their considerable influence to delay that day as long as possible.
In the meantime, we will keep eating – but we need to ask just how well?
Deborah Rich raises olives and two children in Monterey County, California, and frequently writes about the interaction of human nature and nature for the San Francisco Chronicle.
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