A menu of vegetables, fruits, whole grains, and legumes gives your body the nutrition it needs but requires remarkably little menu planning. In this chapter, we will look at how to make sure you are not missing anything. As you will see, getting the nutrition you need is very easy. In fact, much of this chapter aims to convince you not to worry about nutrients that need little, if any, attention.
Even so, there are a few things that merit some discussion—I’m thinking especially of vitamin B12 and vitamin D—so let’s start there.
VITAMIN B12 • You need B12 for healthy nerves and healthy blood cells. But B12 is not made by either plants or animals; it is made by bacteria. Some people have speculated that, before the advent of modern hygiene, the bacteria in soil, on plants, on our fingers, or in our mouths gave us the B12 traces we need. Whether that was ever true is hard to say, but it is certainly not true today.
Meat-eaters get some B12 because the bacteria in a cow’s gut make it, and traces pass into meat and milk. We have similar bacteria in our digestive tracts, but scientists believe that it is produced too far down in our intestines to be absorbed.
A great many people have trouble absorbing B12 from animal products. That’s because B12 is bound to proteins. If you are not producing much stomach acid—perhaps because you are taking an acid-blocking medication or are simply not making as much stomach acid as you used to—you may not be absorbing B12 very well. Also, metformin reduces B12 absorption, and because metformin is the most commonly prescribed medicine for type 2 diabetes, you can see why people—especially those with diabetes—might run low.
The answer is a supplement. Unlike the vitamin B12 found in animal products, the B12 in supplements is easily absorbed. The recommended dietary allowance of B12 is tiny—just 2.4 micrograms Per day for adults—and all common multivitamins include more than that. Drugstores and health-food stores also stock supplements containing B12 alone, as well as supplements combining B12 with other B vitamins. They are all fine. There are no risks associated with taking too much B12—the vitamin is safe even if taken in large amounts.
Some foods—including breakfast cereals, soy milk, and nutritional yeast—are fortified with the vitamin, too. But to be sure you are getting the amount you need, it’s a good idea to take a supplement regularly.
VITAMIN D • As we discussed earlier, vitamin D helps your body absorb calcium and helps protect you from cancer, as well as performing other functions. Your body normally produces vitamin D when your skin is exposed to sunlight. When our forebears lived in equatorial Africa, the plentiful sunshine gave them all the vitamin D they needed. But somewhere along the line, our restless ancestors moved to places like North Dakota, Seoul, and Oslo, and sunlight was less plentiful. Moreover, if you are indoors most of the day or you use sunscreen, you are not getting your normal dose of sunlight. So it makes sense to take a supplement. A dose of up to 2,000 international units (IU) Per day appears to be safe.
If you are unsure if you really need a supplement, your doctor can check your vitamin D level. If you are not getting regular sun exposure, however, it is safe to assume that you need a vitamin D supplement.
So vitamin B12 and vitamin D are the two vitamins worth thinking about. A B12 supplement is mandatory and a vitamin D supplement is a good idea.
Let’s have a look at protein, calcium, and iron. These are dietary needs that are often discussed but are really very simple to get.
PROTEIN • Protein is used to repair body tissues and to make various molecules that your body uses. But here is the key: The amount you need is surprisingly modest. Although protein is often a preoccupation of people who are considering a dietary change, most people get far more than they need.
You’ll find plenty of protein in beans, grains, and vegetables. Broccoli, spinach, and other greens are about one-third protein or even more, as a percentage of calories. If that sounds surprising, picture a bull, stallion, elephant, or giraffe. All of them build their massive bodies entirely from plant-based foods.
Here are a few more details: You probably know that proteins are built from amino acids. Like beads in a necklace, the amino acids link together to form protein strands. Your body can make some of these amino acids, while others (called essential amino acids) cannot be made in your body and have to come from foods. The good news is that all of the essential amino acids—all of the protein building blocks you need—are found in plants. There is no need to carefully combine specific food groups in search of this or that amino acid. Any normal varied diet built from vegetables, fruits, beans, and grains will provide all of the amino acids you need.
This is also true for athletes. Yes, they need more protein than sedentary people do to repair the wear and tear on their bodies. But a plant-based diet still provides more than enough protein, even for the most vigorous athlete.
Bottom line: On any normal, varied, plant-based diet, you’ll get the protein you need without thinking about it. Just as breathing gives you oxygen without your having to measure it, eating foods from plants gives you all the protein you need.
CALCIUM • Your body needs calcium for bone development and many other things. But you do not need dairy calcium. After all, only about 30 percent of the calcium in milk is absorbed by your body. And along with it come lactose (a type of sugar), dairy fats, hormones, and other things you don’t want. There is plenty of highly absorbable calcium in green leafy vegetables. Broccoli, kale, collards, Brussels sprouts, and other greens are loaded with it. Think about it: A cow doesn’t make the calcium found in its milk. A cow simply ingests the calcium in green leafy vegetables—that is, grass. You can do the same, albeit with a tastier selection of greens! Green vegetables are nature’s best calcium source. An exception to this rule is spinach: Unlike other greens, the calcium in spinach is not well absorbed.
Calcium is also found in many other foods, particularly beans. So when it comes to calcium, think “greens and beans.”
IRON • Greens and beans provide iron, too. You already know that you need iron to build hemoglobin, which allows your red blood cells to transport oxygen, and these healthful plant foods provide plenty of it. If you are eating red meat for the iron it contains, keep in mind that cows do not make iron. Cows get iron from the same source as they do calcium—from grass and other plant foods.
It is actually better to get iron directly from plant sources, rather than from meat. Here’s why: Iron in plants is called nonheme iron, which is more absorbable when your body needs more and less absorbable when your body has plenty of iron already. That is important because if your body gets too much iron, it can be harmful to your heart and other organs.
Iron from meat is less desirable. When iron has been processed through a cow’s body, it is called heme iron. Because your body cannot regulate the absorption of heme iron, over the long run you—and many meat-eaters—will accumulate too much iron.
So think “greens and beans,” and you’ll get not only calcium, but iron, too, in a form your body is designed to absorb and regulate.
FAT • You need just traces of fat in your diet, and that quantity is easily obtained from healthful plant sources. There is plenty of healthful fat in walnuts, soy products, flax seeds, and other foods. But let me make one more pitch for green vegetables: Although they do not contain much fat, the traces they do contain supply the healthy fats your body actually needs.
Animal products are often high in “bad” fat—that is, the saturated fat that raises cholesterol levels and is linked to Alzheimer’s disease. It also packs into your cells and contributes to insulin resistance.
Although most plants contain modest quantities of fats—which is good—there are a few exceptions. Nuts, seeds, avocados, olives, and full-fat soy products are high in fat. While their fat is much healthier than the fat found in dairy products and meats (vegetable fats are generally much lower in saturated fat), these fats are still as high in calories as any other fat, so I would encourage you to keep consumption of these fatty foods to a minimum.
So there you have it. Eat a variety of vegetables, fruits, whole grains, and legumes. Avoid adding fats to your foods. Take a vitamin B12 supplement, and add a vitamin D supplement if you are not getting regular sunshine. Do that, and you’ve got complete nutrition.