Nature’s Beneficial Chemistry

The same plant foods that yield carbohydrates (see Chapter 8) are also the source of phytochemicals — natural compounds other than vitamins manufactured only in plants (phyto- is the Greek word for plant).

Phytochemicals, such as coloring agents and antioxidants, are the substances that produce many of the beneficial effects associated with a diet rich in fruits, vegetables, beans, and grains. The best sources of phytochemicals are highly colored vegetables and fruits.

The most interesting phytochemicals in plant foods are antioxidants, hormonelike compounds, and enzyme-activating sulfur compounds. Each group plays a specific role in maintaining health and reducing your risk of certain illnesses, which is one reason the Dietary Guidelines for Americans urges you to have as many as nine servings of fruits and vegetables and several servings of grains every day.

Antioxidants

Antioxidants are named for their ability to prevent a chemical reaction called oxidation, which enables molecular fragments called free radicals to join together, forming what appear to be potentially carcinogenic (cancer-causing) compounds in your body.

Antioxidants also slow the normal wear and tear on body cells, which may be why so many studies suggest that a diet rich in plant foods (fruits, vegetables, grains, and beans) is likely to reduce the risk of chronic conditions, such as heart disease. But you got to get the plants to get the benefit: Stuffing yourself with antioxidant vitamin supplements shows absolutely no effects on heart health.

Hormonelike compounds

Many plants contain compounds that behave like estrogens, the female sex hormones. Because only an animal body can produce true hormones, these plant chemicals are called hormonelike compounds or phytoestrogens (plant estrogen).

The three kinds of phytoestrogens are

Isoflavones, in fruits, vegetables, and beans
Lignans, in grains
Coumestans, in sprouts and alfalfa

The most studied phytoestrogens are the soy isoflavones daidzein and genistein, two compounds with a chemical structure similar to estradiol, the estrogen produced by mammalian ovaries. Like natural or synthetic estrogens, phytoestrogens hook onto sensitive spots in reproductive tissue (breast, ovary, prostate, and so on).

These plant estrogenlike compounds are weaker, so researchers once suggested that they might provide postmenopausal women with the benefits of estrogen (stronger bones and relief from hot flashes) without the higher risk of reproductive cancers associated with hormone replacement therapy (HRT). But repeated animal and human studies suggested that, like natural and synthetic hormones, the plant compounds may stimulate tumor growth while having little effect on menopausal symptoms such as hot flashes.

Bottom line? According to the International Food Information Council, “Further clinical studies will continue to increase understanding of the role of soy in maintaining and improving health.” (For more on soy’s unique proteins, check out Chapter 6.)

Sulfur compounds

Slide an apple pie in the oven, and soon the kitchen fills with an aroma that makes your mouth water and your digestive juices flow. But boil some cabbage and — what is that awful smell? It’s sulfur, the same chemical you smell in rotten eggs.

Cruciferous vegetables (the name comes from crux, the Latin word meaning cross, a reference to their x-shape blossoms), such as broccoli, Brussels sprouts, cauliflower, kale, kohlrabi, mustard seed, radishes, rutabaga, turnips, and watercress, all contain stinky sulfur compounds such as sulforaphane glucosinolate (SGSD), glucobrassicin, gluconapin, gluconasturtin, neoglucobrassicin, and sinigrin whose aromas are liberated when the food is heated.

Many researchers previously believed that these natural chemicals could tell your body to rev up to fight cancer, but the evidence from multiple studies in the early 2000s, when the cruciferous veggies movement was at its height, is conflicting.

Researchers employ two basic types of studies to assess a link between cause and effect, or in this case, eating cruciferous vegetables and avoiding various forms of cancer. The first type is a case control study, which compares patients with a disease or condition to healthy people, looking back at their histories to see what they may or may not have in common.

The second type is a cohort study, in which researchers establish a base of subjects, say 1,000 women age 25 to 40, and follow them for several years to see whether a specific behavior, such as a diet rich in cruciferous vegetables, will or will not produces a specific effect, such as a lower risk of cancer.

In 2001, a report from a case control study published in the Journal of the American Medical Association showed that eating lots of cruciferous veggies led to a lower risk of breast cancer. But the same year, an overview of a number of studies conducted in the United States, Canada, Sweden, and the Netherlands found no such link.

In 2000, the Netherlands Cohort Study on Diet and Cancer suggested that women — but not men — who ate lots of cruciferous vegetables were at lower risk of colon (but not rectal) cancer. But in 2000, 2001, and 2003, three American and Dutch studies found no link.

From 1992 to 2000, several American and European cohort studies failed to find a definite link between cruciferous vegetables and the risk of lung cancer. One American analysis of data from the long-running Nurses Health Study and the Health Professionals study did show that women — but not men — who ate more than five servings a week were at lower risk.

Some case control studies between 1999 and 2000 suggested that a diet rich in cruciferous veggies might reduce a man’s risk of prostate cancer, but multiple studies in the Netherlands (1998), the United States (2003), and Europe (2004) turned up little or no association.

But then in 2005, a trial conducted in China by researchers from Johns Hopkins Medical School, the University of Minnesota Cancer Institute, and the Qidong Liver Cancer Institute of Jiao Tong University (Shanghai) produced a possible explanation for why cruciferous vegetables might reduce the risk of some forms of cancer. The sulforaphane in Brussels sprouts inactivates aflatoxins — toxins released by molds on grains, such as rice, that are known to damage cells and, yes, increase the risk of cancers of the stomach and liver, two diseases more common in China than elsewhere in the world. In 2014, researchers from Johns Hopkins School of Medicine, the University of Pittsburgh, and the Qidong (China) Liver Cancer Institute confirmed that sulforaphane produces a cellular reaction that protects against carcinogenic changes. Clearly, this is a subject of interest.

What should you do while waiting for a final answer? Enjoy your phytochemicals. Dig into those veggies, fruits, and grains. Then turn to Chapter 12 to find out why you need to wash them down with plenty of cold, clear water.

Exploring the Natural and Synthetic Nature of Food Additives

Food additives may be natural or synthetic. For example, vitamin C is a natural preservative. Butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) are synthetic preservatives. To ensure your safety, both the natural and synthetic food additives used in the United States come only from the group of substances known as the generally recognized as safe (GRAS) list.

All additives on the GRAS list

Are approved by the Food and Drug Administration (FDA), meaning that agency is satisfied that the additive is safe and effective
Must be used only in specifically limited amounts
Must be used to satisfy a specific need in food products, such as protection against molds
Must be effective, meaning that they must actually maintain freshness and safety
Must be listed accurately on the label

Nutrient additives

Vitamin D, which is added to virtually all milk sold in the United States, is one example of a clearly beneficial food additive. Most U.S. bread and grain products are fortified with added B vitamins, plus iron and other essential minerals to replace what’s lost when whole grains are milled into white flour for white bread. Some people say that people would be better off simply sticking to whole grains, but adding vitamins and minerals to white flours enhances a product that many people prefer.

Some nutrients are also useful preservatives. For example, as Chapter 10 explains, vitamin C is an antioxidant that slows food spoilage and prevents destructive chemical reactions, which is why American food packagers must add a form of vitamin C (isoascorbic acid or sodium ascorbate) to bacon and other luncheon meats to prevent the formation of potentially cancer-causing compounds.

Color additives

Colors, flavoring agents, and flavor enhancers make food look and taste better. Like other food additives, these three may be either natural or synthetic.

Natural colors

One good example of a natural coloring agent is beta carotene, the yellow pigment extracted from many fruits and vegetables and used to turn naturally white margarine to buttery yellow.

Some other natural coloring agents are annatto, a yellow-to-pink pigment from a tropical tree; chlorophyll, the green pigment in green plants; carmine, a reddish extract of cochineal (a pigment from crushed beetles); saffron, a yellow herb; and turmeric, a yellow spice.

NEW COLORS FOR CLASSIC VEGGIES

What color is your cauliflower? Once upon a time, the only answer was “white.” Today, as every serious foodie knows, cauliflower also comes in green, purple, and a smashing orange that first bloomed by accident among the crops grown by a Toronto, Canada, vegetable producer, the result of a completely natural and completely unexpected cross pollination between a carrot and a cauliflower. After that, the scientists at the New York State Agricultural Experiment Station in Geneva (NY) and various European food labs stepped in with carefully conducted cross-breeding to brighten up the cauliflower’s white florets.

Whether orange cauliflower is prettier than the white is a personal decision, but there's no question that it's more nutritious. The color comes from beta carotene, a natural pigment your body converts to vitamin A, and an orange cauliflower has about 25 times more convertible carotenoids than a white one. A purple cauliflower has red and blue anthocyanins, pigments found naturally in blueberries, beets, red cabbage, and strawberries. As for lime green, that’s a cauliflower crossed with broccoli, which contributes green chlorophyll along with yellow carotenoids.

Carotenoids, anthocyanins, and chlorophyll are all antioxidants that protect a plant from changes due to exposure to oxygen. They may also do something similar for human beings. The theory is that when we eat foods with antioxidant plant pigments, the pigments become chemopreventers, substances thought to stop trouble before it starts by keeping molecular fragments, called free radicals, from hooking up to form compounds that can damage cells, causing changes that may lead to heart disease, cancer, and other age-related degenerative diseases.

Notice the carefully chosen words theory, may, and thought to because science is still waiting for positive proof. Nonetheless, this health benefit is potentially so valuable that from time to time people have tried to take the pigments out of the plants and put them and their benefits into a pill. That doesn’t seem to work. In one famous incident in the late 1980s, people who took beta carotene supplements to lower their risk of various kinds of cancer turned out to raise their risk instead.

To get the goods, you have to eat the food, so another benefit of cross-breeding veggies is making food look more inviting. On the other hand, some colors that aren't natural to food can be definite turn-offs. In psychological studies, the classic “yuck” food has always been mashed potatoes tinted blue with food coloring. But when JetBlue cabin attendants hand out bags of blue (get it?) potato chips made from a naturally blue variety of potatoes, they go like hot cakes. Go figure.

Synthetic colors

An example of a synthetic coloring agent is FD&C Blue No. 1, a bright blue pigment made from coal tar and used in soft drinks, gelatin, hair dyes, and face powders, among other things.

And, yes, as scientists have discovered more about the effects of coal-tar dyes, including the fact that some are carcinogenic, many of these coloring agents have been banned from use in food in one country or another but are still allowed in cosmetics.

Flavor additives

Every cook worth his or her spice cabinet knows about natural flavor ingredients, especially salt, sugar, vinegar, wine, and fruit juices.

Artificial flavoring agents reproduce natural flavors. For example, a teaspoon of fresh lemon juice in the batter lends cheesecake a certain je ne sais quoi (French for “I don’t know what” — a little something special), but artificial lemon flavoring works just as well. You can sweeten your morning coffee with natural sugar or with the artificial sweetener saccharin. (For more about substitute sweeteners, see Chapter 19.)

Flavor enhancers are a slightly different kettle of fish. They intensify a food’s natural flavor instead of adding a new one. The best-known flavor enhancer is monosodium glutamate (MSG), widely used in Asian foods.

Although it improves flavor, MSG may also trigger short-term, generally mild reactions, such as headaches, flushing, sweating, facial numbness and tingling, and rapid heartbeat in people sensitive to the seasoning.

Preservatives

Food spoilage is a totally natural phenomenon. Milk sours. Bread molds. Meat and poultry rot. Vegetables wilt. Fats turn rancid. The first three kinds of spoilage are caused by microbes (bacteria, mold, and yeasts). The last two happen when food is exposed to oxygen (air).

All the preservative techniques explained in Chapters 20 and 21— cooking, chilling, canning, freezing, and drying — prevent spoilage either by slowing the growth of the organisms that live on food or by protecting the food from the effects of oxygen. Chemical preservatives do essentially the same thing:

Antimicrobials are natural or synthetic preservatives that protect food by slowing the growth of bacteria, molds, and yeasts.
Antioxidants are natural or synthetic preservatives that protect food by preventing food molecules from combining with oxygen (air).

Table 22-1 is a representative list of some common preservative chemicals and the foods in which they’re found.

Table 22-1 Preservatives in Food

Preservative	Found in …
Ascorbic acid^*	Sausages, luncheon meats
Benzoic acid	Beverages (soft drinks), ice cream, baked goods
BHA (butylated hydroxyanisole)	Potato chips and other foods
BHT (butylated hydroxytoluene)	Potato chips and other foods
Calcium propionate	Breads, processed cheese
Isoascorbate^*	Luncheon meats and other foods
Sodium ascorbate^*	Luncheon meats and other foods
Sodium benzoate	Margarine, soft drinks

*A form of vitamin C

Other additives in food

Food chemists use a variety of the following types of natural and chemical additives to improve the texture of food or prevent mixtures from separating:

Emulsifiers, such as lecithin and polysorbate, keep liquid-plus-solids, such as chocolate pudding, from separating into liquid and solids. They can also keep two unfriendly liquids, such as oil and water, from divorcing so that your salad dressing stays smooth.
Stabilizers, such as the alginates (alginic acid) derived from seaweed, make food such as ice cream feel smoother, richer, or creamier in your mouth.
Thickeners are natural gums and starches, such as apple pectin or cornstarch, that add body to foods.
Texturizers, such as calcium chloride, keep foods such as canned apples, tomatoes, or potatoes from turning mushy.

Although many of these additives are derived from foods, their benefit is aesthetic (the food looks better and tastes better), not nutritional.

Determining the Safety of Food Additives

The safety of any chemical approved for use as a food additive is determined by evaluating its potential as a toxin, carcinogen, or allergen, each of which I define in the following sections.

Defining toxins

A toxin is a poison. Some chemicals, such as cyanide, are toxic (poisonous) in very small doses. Others, such as sodium ascorbate (a form of vitamin C), are nontoxic even in very large doses. All chemicals on the generally recognized as safe (GRAS) list are considered nontoxic in the amounts that are permitted in food.

By the way, both vitamin C and cyanide are natural chemicals — one beneficial, the other not so much.

Explaining carcinogens

A carcinogen is a substance that causes cancer. Some natural chemicals, such as aflatoxins (poisons produced by molds that grow on peanuts and grains), are carcinogens. Some synthetic chemicals, such as specific dyes, are also potentially carcinogenic.

In 1958, driven by a fear of potentially carcinogenic pesticide residues in food, New York Congressman James Delaney proposed, and Congress enacted into law, an amendment to the Food, Drug, and Cosmetic Act that banned from food any synthetic chemical known to cause cancer (in animals or human beings) when ingested in any amount, no matter how small. (The Delaney clause didn’t apply to natural chemicals, even those known to cause cancer.)

For a time, the only exception to the Delaney clause was saccharin, which was exempted in 1970. Although ingesting very large amounts of the artificial sweetener is known to cause bladder cancer in animals, no similar link was ever found to human cancers. Nonetheless, in 1977, Congress required all products containing saccharin to carry a warning statement: “Use of this product may be hazardous to your health. This product contains saccharin, which has been determined to cause cancer in laboratory animals.”

When the Delaney clause was introduced, ingredients such as additives were measured in parts (of the additive) per thousand parts (of the product). Today, scientists have the ability to measure an ingredient in parts per trillionths. As a result, the zero-risk standard of the Delaney clause in regard to pesticide residue in food was repealed and replaced with a standard of “reasonable risk.” The saccharin warning was lifted in 2000.

THE NITRATE/NITRITE CONUNDRUM

Some preservatives are double-edged — good and not-so-good at the same time. For example, nitrates and nitrites are effective preservatives that prevent the growth of disease-bearing organisms in cured meat. But when they reach your stomach, nitrates and nitrites react with natural ammonia compounds called amines to form nitrosamines, substances known to cause cancer in animals fed amounts of nitrosamines much higher than found in any human food.

But avoiding foods with added nitrates and nitrites won’t prevent your having to cope with nitrosamines. Beets, celery, eggplant, lettuce, radishes, spinach, and turnip greens all contain naturally occurring nitrates and nitrites, sometimes at higher levels than in cured meat products. When their nitrates and nitrates shake hands in your stomach, they make — you got it! — nitrosamines.

To take the sting out of added nitrates and nitrites in processed foods such as cured meats, the USDA, which regulates meat, fish, and poultry, sensibly requires manufacturers to add an antioxidant vitamin C compound, such as sodium ascorbate, or an antioxidant vitamin E compound (a tocopherol). The antioxidant vitamins prevent the formation of nitrosamines while boosting the antimicrobial powers of the nitrates and nitrites.

Listing allergens

Allergens are substances that trigger allergic reactions. Some foods, such as peanuts, contain natural allergens that can provoke the fatal allergic reaction known as anaphylaxis.

The best-known example of an allergenic food additive is the sulfites, a group of preservatives that

Keep light-colored fruits and vegetables (apples, potatoes) from browning when exposed to air
Prevent shellfish (shrimp and lobster) from developing black spots
Reduce the growth of bacteria in fermenting wine and beer
Bleach food starches
Make dough easier to handle

Sulfites are safe for most people but not for all. In fact, the FDA estimates that 1 out of every 100 people is sensitive to these chemicals; among people with asthma, the number rises to 5 out of every 100. For people sensitive to sulfites, even infinitesimally small amounts may trigger a serious allergic reaction, and asthmatics may develop breathing problems by simply inhaling fumes from sulfite-treated foods.

In 1986, the FDA tried banning sulfites from food but lost in a court case brought by food manufacturers, so two years later the agency wrote rules to protect sulfite-sensitive people.

Today, sulfites are not considered GRAS for use in

Meats
Foods that are an important source of vitamin B1 (thiamin), a nutrient sulfites destroy
Fruits and veggies served raw (think salad bars), or described as “fresh” (think fruit salad)

Sulfites are permitted in some foods, such as dried fruit, but the package must list sulfites if the additives account for more than ten parts sulfites to every million parts food (10 ppm). These rules, plus plenty of press information about the risks of sulfites, have led to a dramatic decrease in the number of sulfite reactions.

For more on allergens in food, check out Chapter 23.

Beyond Additives: Foods Nature Never Made

Genetically engineered foods, also known as GMOs or bioengineered foods, are foods with extra genes added artificially through special laboratory processes. Like preservatives, flavor enhancers, and other chemical boosters, the genes — which may come from plants, animals, or microorganisms such as bacteria — are used to make foods more resistant to disease and insects, more nutritious, and better tasting.

Genetic engineering may also help plants and animals grow faster and larger, thus increasing the food supply. The Big Question is, “Are genetically engineered foods safe?”

Many consumers have doubts. To enable them to make a clear choice — “Yes, I’ll take that biotech food” or “No, I won’t” — the European Union requires food labels to specifically state the presence of any genetically altered ingredients. In the United States, the FDA currently requires wording on labels to alert consumers to genetic engineering only when it results in an unexpected added allergen (such as corn genes in tomatoes) or changes the nutritional content of a food.

Does the wording on the label matter to consumers? Are most willing to accept genetically altered foods? The answer depends on who you ask and how you ask.

The International Food Information Council (IFIC), a trade group for the food industry, accepts the current label-wording rules. The Center for Science in the Public Interest (CSPI), a Washington-based consumer advocacy group, wants to see the words genetically altered on all foods that have been, well, genetically altered. In 2005, each organization conducted a survey that seemed designed to bolster its point of view.

For example, IFIC’s survey says that nearly two-thirds (61 percent) of Americans expect food technology to serve up better-quality, better-tasting food. CSPI’s competing survey says, “Not so fast.” The difference may lie in the questions. IFIC’s emphasizes the benefits of biotech; CSPI’s leans more heavily on the drawbacks. For example:

CSPI Version: Would you buy food labeled “genetically engineered”? Forty-three percent said yes.
IFIC Version: Would you buy a food if it had been modified by biotechnology to taste better or fresher? Or stay fresher? Fifty-four percent said yes.

Ten years later, little has changed. In 2015, when the Neilsen company conducted an online poll of 30,000 people in 60 countries about which health benefits they considered “very important” when buying food, the two top answers were “all-natural” and “GMO-free.”

In the end, despite a slight wariness about exploring new nutritional ground, Americans are intrigued by the promise of food innovations and willing to give the whole idea a try. Only 32 percent of them considered “GMO-free” very important versus 47 percent in Europe and 46 percent in Latin America.

Eventually, the proof of GMOs’ promise will be in the (genetically engineered) pudding.

Better Eating through Chemistry