The 2010 Dietary Guidelines Advisory Committee called potassium one of the key nutrients Americans are deficient in. According to the report, we consume an average of 2,400 milligrams a day—only about half of the adequate intake (or AI, the recommended average daily nutrient intake level set by the Institute of Medicine) of 4,700 milligrams a day. “We’ve been so focused on getting less sodium that we’ve neglected the importance of getting enough potassium,” says Kleiner.
The fix: Shoot for three or four servings of potassium-packed foods a day, recommends Gerbstadt. “Most people think first of bananas, but there are many other foods just as rich or better,” she says. For example, one medium potato (including the skin) contains 926 milligrams of potassium, compared with 422 in a medium banana. Foods especially high in potassium include spinach, carrot juice, prune juice, beet greens, white beans, papayas, dried apricots, avocados and salmon. Warning: Do not take a potassium supplement without a doctor’s OK. If you have kidney problems or take diuretics, you may have trouble excreting high levels of this mineral from your body.
Power nutrient: Vitamin B12
Biggest benefit: A healthy nervous system
The nervous system, which includes the brain, depends on B vitamins to help it run smoothly. So getting enough of this nutrient is key to staying mentally on the ball. In a randomized trial, researchers in the United Kingdom showed that a high dose of B vitamins, including B12, B6 and folic acid, slowed the rate of brain atrophy in elderly men and women suffering from mild cognitive impairment. “People who are vitamin B12 deficient have problems thinking, walking and moving. The vitamin plays a role in keeping us sharp both physically and mentally,” says Kleiner.
B12 also plays a crucial role in producing red blood cells, and a shortage of the vitamin can lead to a decline in these oxygen carriers, a serious condition known as pernicious anemia.
In addition, a shortfall of B12 can lead to an overabundance in the body of a substance called homocysteine, which is used to build protein. An excess of homocysteine has been associated with an elevated risk for strokes and certain types of heart disease.
Who’s falling short: Anyone over 50; strict vegetarians or vegans
Getting vitamin B12to circulate in your body is a complicated matter. First, stomach acids have to dissolve the protein that the B12was attached to when you ate, say, a piece of steak. Then, before the vitamin can move through your gastrointestinal tract, it has to combine in the stomach with a protein called intrinsic factor. As we grow older, the levels of both stomach acid and intrinsic factor decrease, so it becomes more challenging for the body to utilize B12. “A deficit is not necessarily about how little B12you eat. It’s often about not being able to absorb the vitamin properly,” says Gerbstadt. Result? Up to 39 percent of people over 50 are walking around with low levels of this nutrient.
A deficiency can also arise from your diet. Since B12 is found almost exclusively in animal products, strict vegetarians or vegans who eschew not just meat but also eggs and dairy products can be prone to shortfalls.
The fix: While vitamin B12 is abundant in animal foods, including fish, meat, eggs and dairy, because of the absorption issue, the National Academy of Sciences recommends that people over 50 play it safe by getting some synthetic B12 from fortified foods (breakfast cereals, for instance) or supplements. The advantage of the synthetic form: Your body can use it without first processing it via stomach acid. For those who go the supplement route, Greenfield recommends taking 25 to 50 micrograms a day in a sublingual form (you put a lozenge under the tongue until it dissolves; the large number of blood vessels there helps the B12 get absorbed readily). B12 injections are also a possibility and are especially useful if you have low levels of intrinsic factor in your stomach.
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