Good food sources: If you like oysters, they are a go-to food for zinc. They contain more zinc per serving than any other food. Poultry, crab and lobster, beans, nuts, whole grains, fortified breakfast cereals, and dairy foods such as milk and yogurt are also good sources.
Safety: Overdosing on zinc can depress the immune system, interfere with wound healing, cause problems with taste and smell, and lead to hair loss and skin problems. High zinc intake may also promote the development or growth of prostate cancer. The advantage of getting your zinc from food, rather than from supplements or lozenges, is that it’s hard to get too much from food. Getting more than 15 milligrams a day of zinc from supplements isn’t a good idea unless it is for a specific medical condition.
PUTTING IT INTO PRACTICE
You pay top dollar to insure your home and your car. You may even have the kind of life insurance you’d rather not have a loved one collect. A far cheaper and more personally gratifying kind of life insurance comes from a daily multivitamin with added minerals.
Research is pointing ever more strongly to the conclusion that several ingredients in a standard multivitamin—especially vitamins B6 and B12, folic acid, vitamin D, and beta-carotene—are essential players in preventing heart disease, cancer, osteoporosis, memory loss, and other chronic diseases. A year’s supply costs under $40, or about a dime a day. That’s an excellent nutritional bang for your buck.
I use the term “insurance” for good reason. A multivitamin can’t in any way replace healthy eating. It gives you barely a scintilla of the vast array of healthful nutrients found in food. It doesn’t deliver any fiber. Or taste. Or enjoyment. The only thing it can do is offer a nutritional backup or fill in the nutrient holes that can plague even the most conscientious eaters. For example, eating more fruits and vegetables is great, but it won’t give you much in the way of vitamin D. Adding more whole grains to your diet is also wonderful, but it won’t net you much vitamin B6. Older people and those with digestive problems may not be able to absorb enough vitamin B12 from food. Those who regularly drink alcohol may need extra folic acid to make up for alcohol’s folate-reducing effects. So taking a daily multivitamin is a safe, rational plan that complements good eating but can never replace it.
Here are the eight vitamins and minerals that many people don’t get enough of from their diets, so it make sense to get them via a standard multivitamin-multimineral pill:
• beta-carotene
• folic acid
• vitamin B6
• vitamin B12
• vitamin D
• vitamin E
• iron
• zinc.
Taking a multivitamin-multimineral pill every day is a reasonable option that provides a wider nutritional safety net. For menstruating women, especially those who eat little or no red meat, a multivitamin-multimineral supplement will provide their extra iron requirements. Also, the folic acid in this pill will fulfill the recommendation by the Centers for Disease Control that all women who might possibly become pregnant should take supplemental folic acid to minimize the risk of neural tube birth defects.
You don’t need a designer vitamin, a name-brand vitamin, or an “all-natural” formulation. A standard, store-brand, RDA-level multivitamin is a perfectly fine place to start. Look for labels that say the product meets the standards of the United States Pharmacopeia (USP). This organization sets manufacturing standards for medications and supplements sold in the United States. The less preformed vitamin A (retinol) in the multivitamin and the more beta-carotene, the better. Choose a supplement that contains no more than 2,000 IU of preformed vitamin A.
For most men and women, an extra vitamin E supplement is okay. Even though the ending hasn’t yet been written to the vitamin E story, at least 400 milligrams a day, and possibly more, may be needed for optimal health. Standard multivitamins contain only 30 IU.
Extra vitamin D is definitely worth pursuing. Standard multivitamins offer 400 to 600 IU, half of what appears to be needed for optimal health.
Some companies make supplements that replace most of the preformed vitamin A with beta-carotene and contain adequate doses of vitamin D. I recommend looking for one of these, because it is too easy to get too much preformed vitamin A. One example is the Basic One multivitamin formulated by Dr. Kenneth Cooper, founder of the Cooper Clinic in Dallas. It contains plenty of vitamin A (2,000 IU), all in the form of beta-carotene, along with 2,000 IU of vitamin D and 200 IU of vitamin E. Menstruating women should get the version that includes iron, which men and postmenopausal women don’t need.
So far there’s no consensus on ideal vitamin intakes because scientific knowledge about them is still evolving. We could definitely use more evidence about the true benefits of the commonly used vitamins. At the same time, harm isn’t likely when they are taken in reasonable doses, and the cost is minimal. In this situation, it seems to be a bit foolish to demand that all the evidentiary i’s be dotted and t’s be crossed before acting.
New Hope for Multivitamins
* * *
Most vitamin studies have looked at individual vitamins, like folic acid or vitamin E, or combinations of antioxidants, with or without minerals. The Physicians’ Health Study II took a different path: it examined the health effects of a standard, over-the-counter, multivitamin-multimineral supplement (Centrum Silver). The results were promising.
The researchers recruited more than 14,000 older male physicians. Half took Centrum Silver for up to fourteen years, while the other half took an identical-looking placebo. At the end of the trial, there was an 8 percent reduction in the risk of developing any type of cancer in the multivitamin group compared to the placebo group.40 Much of this was due to a reduction in risk of colorectal cancer as predicted by previous prospective cohort studies.
The multivitamin-multimineral supplement didn’t appear to help prevent cardiovascular disease or protect memory or thinking skills.41
Two things about this trial make it noteworthy: It would never have uncovered a connection between multivitamin use and cancer, especially colorectal cancer, if the study hadn’t lasted longer than ten years, which is longer than most vitamin trials. In addition, the participants were probably the best-nourished group of men ever studied, and despite that a benefit was seen for a daily multivitamin. It is likely that the benefits would have been more extensive in a group that was less well nourished.
Recommended Daily Intake of Vitamins and Minerals for Adults (Established by the Institute of Medicine)
Vitamin (Common Names)
Recommended Dietary Allowance (RDA) or Daily Adequate Intake (AI)*
Upper Limit
Women
Men
Vitamin A (preformed = retinol; beta-carotene can be converted to vitamin A)
700 micrograms (2,333 IU)
900 micrograms (3,000 IU)
3,000 micrograms (about 10,000 IU)
Thiamin (vitamin B1)
1.1 milligrams
1.2 milligrams
Not known
Riboflavin (vitamin B2)
1.1 milligrams
1.3 milligrams
Not known
Niacin (vitamin B3, nicotinic acid)
14 milligrams
16 milligrams
35 milligrams
Pantothenic acid (vitamin B5)
5 milligrams*
5 milligrams*
Not known
Vitamin B6 (pyridoxal, pyridoxine, pyridoxamine)
19–50: 1.3 milligrams
51+: 1.5 milligrams
19–50: 1.3 milligrams
51+: 1.7 milligrams
100 milligrams
Vitamin B12 (cobalamin)
2.4 micrograms
2.4 micrograms
Not known
Biotin
30 micrograms*
30 micrograms*
Not known
Vitamin C (ascorbic acid)
75 milligrams
*(Smokers:
Add 35 milligrams)
90 milligrams*
2,000 milligrams
Choline
425 milligrams*
550 milligrams*
3,500 milligrams
Vitamin D (calciferol)
19–50: 55 micrograms (200 IU)
51–70" 1- micrograms (400 IU)
71+:15 micrograms (600 IU)
19–50: 15 micrograms (2,000 IU)
51–70: 10 micrograms (400 IU)
71+:15 micrograms (600 IU)
1000 micrograms (4,000 IU)
Vitamin E (alpha-tocopherol)
15 milligrams
15 milligrams
1,000 milligrams (nearly 1,500 IU natural vitamin E; 2,200 IU synthetic)
(15 milligrams equals about 22 IU from natural sources of vitamin E and 33 IU from synthetic vitamin E)
Folic acid (folate, folacin)
400 micrograms
400 micrograms
1,000 micrograms
Vitamin K (phylloquinone, menadione)
90 micrograms*
120 micrograms*
Not known
Mineral
Recommended Amount (Daily RDA or Daily AI)
*Upper Limit
Women
Men
Calcium
31–50: 1,000 milligrams
51+: 1,200 milligrams
31–70: 1,000 milligrams
51+: 1,200 milligrams
2,500 milligrams
19–50: 2.3 grams*
19–50: 2.3 grams*
Not known
Chloride
51‚–70: 2.0 grams*
51–70: 2.0 grams*
701+: 1.8 grams*
70+: 1.8 grams*
Chromium
31–50: 25 micrograms*
51+: 20 micrograms*
31–50: 35 micrograms*
51+: 30 micrograms*
Not known
Copper
900 micrograms
900 micrograms
10,000 micrograms
Fluoride
3 milligrams
4 milligrams
10 milligrams
Iodine
150 micrograms
150 micrograms
1,100 micrograms
Iron
31–50: 18 milligrams
51+: 8 milligrams
31-50+: 8 milligrams
51+: 8 milligrams
45 milligrams
Magnesium
19–30: 310 milligrams
31–70+: 320 milligrams
19–30: 400 milligrams
31–70+: 420 milligrams
350 milligrams from supplements
Manganese
1.8 milligrams*
2.3 milligrams*
11 milligrams
Molybdenum
45 micrograms
45 micrograms
2,000 micrograms
Phosphorus
700 milligrams
700 milligrams
31–70: 4,000 milligrams
71+: 3,000 milligrams
Potassium
4,700 milligrams*
4,700 milligrams*
Not known
Selenium
55 micrograms
55 micrograms
400 micrograms
Sodium
19–50: 1,500 milligrams*
51–70: 1,300 milligrams*
70+: 1,200 milligrams*
19–50: 1,500 milligrams*
51–70: 1,300 milligrams*
70+: 1,200 milligrams*
Not determined
Zinc
8 milligrams
11 milligrams
40 milligrams
* RDA: the average daily dietary intake sufficient to meet the nutrient requirement of 97–98 percent of healthy individuals in a particular group according to stage of life and gender. AI: a recommended intake when an RDA can’t be determined. Micronutrients with AIs are noted by *.
CHAPTER TWELVE
* * *
The Planet’s Health Matters Too
WHAT YOU AND I EAT unquestionably affects our individual health. What we eat collectively affects the health of our planet and thus the health of our children, grandchildren, and future generations.
In the first edition of this book, published sixteen years ago, climate change was becoming a global concern. I included a few paragraphs on the effects of different dietary choices on the production of greenhouse gases and other environmental impacts. What we have experienced and learned since then has made climate change a major and urgent issue. We don’t need sophisticated measurements or statistical models to know this is happening; it is happening right before our eyes.
When I first worked in Tanzania as a medical student in the 1960s, the top of Mount Kilimanjaro was covered in snow year-round. Today, that snow has almost disappeared and will soon be gone. Icebergs are retreating and vanishing around the world. The Arctic Ocean is becoming open for shipping on an annual basis. Deadly storms, droughts, floods, and other extreme weather events are occurring with increasing regularity.
Why mention this in a book on healthy eating? Climate directly affects food production, and food production can affect climate and the environment.
THREE KEY ISSUES
Growing your own food in a hand-tended garden has minimal effect on the environment, especially if you use just the right amount of natural fertilizer, rely on natural strategies to control weeds and pests, and grow only as much as you need. But few of us are able to get most of the food we need this way. Understanding how food is produced, and then making small changes in the food you buy and eat, can help lighten your carbon footprint on the planet.
Farming and food production can harm the environment in many ways. Here are four of the most important:
Climate change. Fossil fuels are burned to make fertilizer and pesticides, pump irrigation water, plow fields, harvest crops, process food, and transport it—sometimes thousands of miles. Burning fossil fuels generates carbon dioxide, the main greenhouse gas responsible for trapping heat in the atmosphere. On top of this, cattle, sheep, and other ruminant animals grown for food generate and release methane as part of their natural digestive process. This gas is twenty-five times more powerful than carbon dioxide at trapping heat.
Feeding grain that has been produced by industrial farming to cattle, which convert it to meat or milk, is far less energy efficient and produces more greenhouse gases than eating that grain directly. In an American feedlot, it takes between 15 and 20 pounds of grain to produce 1 pound of beef.
Although the numbers vary depending on how emissions are calculated, the U.S. Environmental Protection Agency estimated that, in 2015, agriculture was responsible for 7.9 to 9 percent of the country's emissions of carbon dioxide and methane, the two leading greenhouse gases.1 Between 80 and 90 percent of this is the result of food production; the rest comes from packaging, refrigeration, and transportation. The members of the 2015–2020 Dietary Guidelines Scientific Advisory Committee, after their initial report was censored by industry-influenced members of Congress, independently published an updated review on the environmental effects of dietary choices.2
Water contamination and depletion. American agriculture also creates water pollution. Fertilizer, herbicides, and pesticides run off farmland into rivers and lakes and eventually make their way into the oceans. Manure from animal feedlots and from fish farming does the same thing. The influx of nutrients often causes huge blooms of algae. These can produce toxins that can harm other aquatic organisms, livestock, pets, and even humans. Decomposition of dying and dead algae can use up most or all of the oxygen in the water, which kills fish and other aquatic animals. The Gulf of Mexico is just one example of this. As the Mississippi River flows from Minnesota to Louisiana, it picks up nutrient-rich runoff from much of the United States’ agriculture belt and deposits it in the Gulf. In the summer of 2016, the algae bloom and subsequent die-off created a dead zone alo
ng the continental shelf along the coasts of Louisiana and east Texas that was nearly 7,000 square miles, or about the size of the state of Connecticut.
In some regions of the world, water is pulled from aquifers (underground layers of rock that hold water) to irrigate crops faster than it is replaced by rain and runoff. In parts of California and the Midwest, this is forcing farmers to drill ever-deeper wells. In India, heavy demand for this underground water is depleting the aquifers, bankrupting farmers and making it difficult for some villages to get drinking water.
Species extinction. Industrial agriculture is also contributing to the extinction crisis—the loss of species around the globe. Some of this is through the use of pesticides and herbicides. In addition, it is also turning diverse landscapes into monocultures. When visiting a meadow near our summer cabin in New Hampshire, my wife, Gail, and I could always be sure we could show our children countless monarch butterflies—until a few years ago. Despite plenty of milkweed, the favored food of these beautiful creatures, their numbers have dwindled: two years ago we found just three or four monarchs and last year saw none. Flying from the East Coast to the West on a clear day provides a picture of the problem: vast fields of crops without the natural habitat needed for monarchs to complete their yearly migration. I also see this when visiting the Willett family farm in Michigan: what were once small fields and hedgerows teeming with diverse life are now massive monocultures of corn and soy.
Monarchs are just one highly visible species in this vulnerable situation—and they still can be saved. However, scientists have documented that we are now in an age of unprecedented species extinction with somewhere between 200 and 2,000 species lost every year. This is an indication of the pressures that our agricultural system is putting on our environment. Narrowing biological diversity will reduce the resilience of ecosystems to survive.
Eat, Drink, and Be Healthy Page 31