How do we know what we know about food and health?
We eat every day, and we know how food makes us feel. Perhaps because of this, many overlook that nutrition is a discipline ded-icated to understanding how what we eat and drink impacts our health and risk of disease, a life science that grew out of analytical chemistry. The Oxford English Dictionary defines nutrition as “1.
The process of providing or obtaining the food necessary for health and growth; 1.1. Food; nourishment; 1.2. The branch of science that deals with nutrients and nutrition, particularly in humans.” The word “nutrient” refers to a chemical necessary for nourishment and growth. In nutrition, there are 6 essential classes of nutrients: fat, carbohydrate, and protein (together known as “macronutrients”);
vitamins and minerals (together known as “micronutrients”); and water. Nutrients can be delivered in diverse packages, whether food or drink, pill or powder. However consumed, they are digested and metabolized and distribute nourishment throughout the body. Each of the nutrients discussed in this chapter (except water; Chapter 14) has unique physiochemical properties whose bioactivity impacts health, longevity, and wellbeing.
Humans have been observing how food impacts health over the course of human evolution. Hunter– gatherers learned, for example, that food led to either pleasure or pain, sustenance or death; and thus history progressed with tales passed from generation to gen-eration. Skip (way) forward to classical Greece, where Hippocrates (c.400 bce), the so- called Father of Western Medicine, is credited
with the adage “Let thy food be thy medicine.” Before then, an-cient India gave birth to Ayurveda (“the science of life”), a system of medicine more concerned with mind– body connections than tra-ditional Western practice. The Vedas (Sanskrit for “knowledge” or
“wisdom”) were first described as early as 5000 bce; they are the oldest sacred texts, dated between the second and first millennia bce, from which Ayurveda later developed into a systematic science with its roots in food and herbs as keys to good health and wellbeing.
Around the same time, China was developing its own theories in a similar fashion, now referred to as traditional Chinese medicine.
Though Hippocrates’ words are catchy— and apt— food is far more than medicine. Ayurveda and other holistic philosophies ar-guably possess a more sophisticated understanding of the power of food and the meaning of total health than traditional Western medicine. This is because Western practice and philosophy focus on treatment (ergo, “medicine”) and have historically disregarded the power of prevention in general, and nutrition in particular. Happily, Eastern and Western philosophies continue to edge closer to each other as Eastern practices now receive public research dollars to test age- old hypotheses. In the meantime, much of what we know today about food and health arises from Western methodologies born during the Scientific Revolution and beyond.
How did the study of food become the science of nutrition?
The late Renaissance period in 16th- century Europe saw a resurging interest in observing and measuring the natural world through disciplines like physics, biology, chemistry, and mathematics, a time described as the “Scientific Revolution.” “Father of Empiricism”
Francis Bacon (1561– 1626) wrote, “There remains simple experi-ence; which, if taken as it comes, is called accident, if sought for, experiment. The true method of experience first lights the candle [hypothesis], and then by means of the candle shows the way [arranges and delimits the experiment]; commencing as it does with experience duly ordered and digested, not bungling or er-ratic, and from it deducing axioms [theories], and from established axioms again new experiment.” Bacon’s tenets are the basis of the scientific method: stating a general research problem and question,
articulating a specific study question to examine the phenomenon, stating a hypothesis, testing the hypothesis by collecting data sys-tematically, interpreting data, and formulating conclusions. The final step is to conduct additional experiments to replicate the findings and reformulate the hypothesis as needed. Theories eventually emerge to explain a group of related phenomena. Still today, the use of the scientific method remains the sole criterion that differentiates science from anecdote, fact from opinion.
Yet it wasn’t until the “Chemical Revolution” in France during the late 18th century that food and health became the subject of sys-tematic scientific inquiry. Employing the tools of analytical chem-istry allowed scientists to begin answering fundamental questions like “How is food metabolized?” In 1770, “Father of Nutrition and Chemistry” Antoine Lavoisier demonstrated that food reacted with oxygen in the body to release heat and water. Later studies in the 1800s investigated the chemical composition of food itself, finding that all victuals included carbon, hydrogen, and oxygen, while some also contained nitrogen. Nitrogen’s unique role in health and lon-gevity stimulated research in both animal models and plant crops.
“Protein” (1839) was among the first major discoveries in the still- nascent nutrition science and the focus of numerous studies and feeding trials.
During these decades, many scientists explored the basic chem-istry of macronutrient (fat, carbohydrate, protein) composition, me-tabolism, and digestion. Others focused on diseases hypothesized to have a nutritional cause, based on observations of populations who shared a common diet. Diseases related to vitamin and mineral deficiencies were rampant, and during the next century research would lead to the discovery of vitamins and minerals and, later, the synthesis of some of these chemicals for addition to the food supply.
Iodine- rich salt, for example, was found to prevent goiter through its role in thyroid functioning (1850). Polished white rice lacked vi-tamin B1 and therefore caused beriberi (1897).
A noteworthy example of a study addressing nutrient defi-ciency was conducted by James Lind, a British physician. Lind saw that British sailors were dying during long sea voyages, observations that had also been made around 200 years prior. In what is thought to be the first ever intervention study, or clin-ical trial, Lind provided lemons and oranges to some sailors as
part of their diet but not others (the control group), learning that the group receiving citrus did not develop the disease. Additional research later showed that some leafy greens and other citrus fruits also prevented scurvy. But it wasn’t until the 1940s, more than 400 years after the first observations of scurvy, and about 175 years following Lind’s trial, that vitamin C (ascorbic acid) was identified as the root cause.
Nutrition scientists today still show compelling associations between food and disease without knowing the bioactive com-ponent responsible for the effect. Lind’s trial, and countless other examples, underscores the importance of food- based research in nu-trition science: we don’t always fully understand why something is happening that leads to reduced disease and suffering (i.e., the mechanism), but the science will eventually catch up. Even so, as nutrition science progressed the discipline became dominated by re-ductionist studies focused on nutrients, rather than foods. Though single- nutrient studies can be illustrative, they can also lead scientists astray when other salient dietary components are not considered in concert, or in the context of an overall diet (Chapter 18).
What is nutrification? What is fortification?
While guidelines and recommendations, policies and programs, are all important, the most powerful application of nutrition knowledge to improve health, arguably, is to add nutrients directly to foods.
“Nutrification” refers to the process of increasing the nutrient con-tent of a food to improve the dietary intake of a population. Scientist Paul Bauernfeind calls it “the most rapidly applied, most flexible, and most socially acceptable form of public health intervention designed to improve the health of a population without requiring education or behavior modification.”
A common method of nutrifying foods is fortification, defined by the Food and Agriculture Organization (FAO) and the World Health Organization (WHO) as “deliberately increasing the content of essential micronutrients in a food so as to improve the nutritional quality of the food supply and provide a public health benefit with minimal risk to health.” Fortification programs may be mandated by law or initiated voluntarily by industry. Foods are selected for
nutrient delivery based on the degree to which a population reg-ularly consumes them, a region- specific assessment. (Alternatives exist: vitamin supplements in the form of powders or pills can be delivered directly to individuals or households, for instance, if food fortification isn’t feasible.) The three major fortification programs employed globally provide vitamin A, iron, and iodine, all of which reduce pain and suffering and mortality, decrease healthcare costs, and curtail lost economic productivity and income.
Iodine, for example, is required for proper functioning of the thyroid gland, and inadequate intakes result in a large neck growth (goiter). Low iodine during pregnancy and early childhood seriously compromises neurological development, leading to severe intellectual disability. Early Chinese writings (c.3600 bce) recorded decreases in goiter following consumption of sea vegetables, and research in the early 19th century identified iodine as the responsible nutrient. Endemic iodine deficiency was observed around the world as well as in the US “goiter belt” (Great Lakes, Appalachia, Northwest) in the early 20th century. Iodized salt was first sold in Michigan in 1924 following a successful pro-gram in Switzerland. Today, more than 120 countries mandate salt fortification. It remains voluntary in the US, though; thus, the American Thyroid Association and the Endocrine Society recom-mend that women take an iodine supplement during preconcep-tion for optimal fetal development (depending on their diet and where they live).
Fortification programs have evolved alongside nutrition knowl-edge, and more recent applications include the prevention of chronic diseases and birth defects. For instance, an association between folate deficiency and neural tube defects (NTDs) was first hypothesized in 1965. Randomized controlled trials (RCTs) in England and Hungary initially showed that supplementation during early pregnancy was protective. Research evidence accumulated, and the early 1990s saw increased efforts in the US to educate women of childbearing age to consume a folate supplement, as the effects occur during the first 28 days of conception, often before a woman is aware of the pregnancy. Experts eventually suggested folate fortification as a better means to prevent NTDs. The US, Canada, and Costa Rica first implemented mandatory fortification in 1998, followed by
Chile (2000) and South Africa (2003). Grain- containing foods like breakfast cereals and bread were nutrified with folate in the US.
Subsequent studies showed a 19– 32% decrease in NTDs such as spina bifida and anencephaly, leading some to call folic acid fortifi-cation “one of the most successful public health initiatives in the past 50– 75 years.” Still, there are always potential adverse consequences from fortification programs, and some have considered whether the increased consumption of folate among those not at risk for NTDs may lead to an increased risk of heart dis ease and some cancers.
While studies have not shown deleterious impacts thus far, research is ongoing.
The addition of the prefix “bio” to the word “fortification”
refers to nutrification through conventional plant breeding and agronomic practices (e.g., selecting cereals for high protein or iron content) or through genetic modification (e.g., modifying genes to produce nutrients). The goal of biofortification is to increase nutri-tional content during production rather than processing “to reach populations where supplementation and conventional fortification activities may be difficult to implement and/ or limited,” according to WHO. Current biofortification projects around the world include beta- carotene (vitamin A) in sweet potato, maize, and cassava; zinc in wheat, rice, beans, maize, and sweet potato; iron in rice, beans, legumes, cassava, and sweet potato; and protein and amino acids in sorghum and cassava. “Golden rice” is another example, in which ge-netic engineering is used to create a rice that produces beta- carotene to combat vitamin A deficiency (VAD; Chapter 2). The project began in 1982 and the first strain was successfully created in 1999. Many studies have since shown that golden rice can help mitigate VAD.
Unfortunately, the crop has struggled due to violent anti- science sentiment and activity, including a 2013 incident when activists destroyed farms undergoing field trials, setting back its progress greatly. There is some indication that genetically engineered (GE) rice may come to market in the near future.
Fortification programs are indeed among public health’s greatest success stories and continue saving countless lives each year all around the world where they are employed— and result in tragic, completely preventable deaths where they are not.
What other methods are used to nutrify foods?
Enrichment, restoration, and supplementation are additional methods that alter nutrient composition. “Enriched” is some-times used synonymously with “fortified,” although in the US it is a legal term that means a food must contain 10% or more of the daily nutrient value compared to the same nonenriched food.
Restoration involves adding back nutrients originally present be-fore food processing; adding vitamins and minerals back to refined white flour (Chapter 10) is a familiar example. “Supplementation”
refers to any product designed to enhance nutritional intake and can take the familiar form of a pill (e.g., vitamin, mineral, herb, amino acid) or any other delivery vehicle (e.g., liquid ex-tract, powder). Supplements can be lifesavers, whether as infant formulas in places where breastfeeding is not possible or as com-plete nutritional shakes for those suffering from health conditions impacting appetite. Conversely, some dietary supplements are ex-pensive products with excessive (non)nutrients that might either lack a solid research base or employ an ineffective chemical formu-lation. In the worst- case scenario, supplements may be adulterated or contaminated, creating a serious health risk. (The dietary sup-plement industry is an important topic beyond the scope of this book; those taking supplements should conduct due diligence on the purity and dose of the product and consult with a nutrition professional.)
While adding essential nutrients to foods to save lives still happens through nutrification efforts like fortification, today’s clever industrialists create copious multivitamin, multimineral products with (perceived) added value, from vitamin- enhanced waters to protein power bars and everything in between. Products like these are often referred to as “nutraceuticals” or “functional foods,” late-20th- century terms that describe the act of making food more nutri-tious to meet (or create) a consumer desire. Yet other products load vitamins and minerals into foods without paying much attention to fundamentals like macronutrient composition, ingredients, and cal-orie content. A Coca- Cola variant with added fiber comes to mind, as do 100% whole grain breakfast cereals loaded in sugar. There are thousands of these types of foods, and it’s not always clear that
they “improve” diets; nutrition knowledge (and common sense) is needed to facilitate informed choices. Thus, while many of today’s products are departures from the original intent of nutrification— to directly prevent or manage disease and save lives— applications will continue to evolve, providing ever more options for consumers to create diets that meet diverse needs and lifestyles.