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Can Supplements Substitute For Real Food?

Is the siren song of the vitamin and supplement aisle at the grocery store calling to you? Fix your blood pressure, your memory, your skin, your gut health or your sex drive all from a few pills a day. Or maybe you know you don’t eat all the vegetables you should so a multivitamin seems like good insurance to cover those gaps.

If you feel like you should be taking a vitamin, you’re not alone. The National Institutes of Health reports that Americans spend more than $36 billion a year on supplements.

Interestingly, the people who take supplements tend to be healthier overall than those who don’t. According to an article published in the Journal of Nutrition, people who took a vitamin or supplement were more likely to have a lower body mass index, have a more nutritious diet, consume more vegetables and less fat, be non-smokers and more physically active. So while the urge to take a vitamin probably means you are interested in leading a healthy lifestyle, a vitamin supplement itself may not actually help you to live that lifestyle.

Comparing Supplements to Food

Consider broccoli. If any healthy food should be converted into a supplement it would have to be broccoli. But a study published in the Journal of Agriculture and Food Chemistry found that the beneficial cancer-fighting compounds in cruciferous vegetables like broccoli were better absorbed when eaten as food rather than taken as a supplement.

“Supplements are sometimes needed but they can only supplement, they can’t substitute for healthy eating. Food should come first,” said Sara Lee Thomas, a registered dietitian at Good Samaritan Regional Medical Center. “For example, if you get five servings of fruits and vegetables a day you will be getting more than 9,000 mg of health-protective phytochemicals, something you just can’t get out of a pill.”

Many respected health authorities agree and advise food-based nutrition.

Role of Supplements and Health

Information published by the World Cancer Fund and the American Institute for Cancer Research recommends meeting nutritional needs through diet alone and not using dietary supplements to prevent cancer. The American Heart Association also recommends eating a healthy diet for heart health rather than taking supplements. Even the American Academy of Pediatrics encourages children who are generally healthy to get their daily nutritional needs from food alone.

“There is no substitute for a healthy diet,” said Thomas. “That being said, science has also found that some nutrients, like vitamin D, are low even in the healthiest of eating plans and some diseases and drugs can create a need for supplements to make up for losses — so supplements are needed and do help in some cases.”

Thomas encourages people to buy good quality supplements and stick to amounts around 100 percent Daily Value (DV). She notes that getting 100 to 115 percent DV for calcium every day from food and supplements helps to keep bones strong but more than 150 percent DV might increase long term risk to the kidneys and heart.

“As the old saying goes, the poison is in the dose,” said Thomas.

For those with less specific health concerns, multivitamins are often taken as insurance in meeting all of the daily nutritional requirements. But studies published in the Archives of Internal Medicine and JAMA show multivitamins do not prolong life or reduce the rate at which people get a chronic disease.

When a Supplement Can Benefit

“Supplements can be beneficial but nutrition is always subject to threshold effects,” said Thomas. “Most research shows health benefits only when you go from low to moderate levels in a nutrient, but with no added benefit when you go from moderate to high levels. This explains why some studies show benefit with supplements and some don’t — it really depends on where you start out and where you end up.” 

Thomas uses vitamin D as an example, a supplement that can help lower blood pressure with about a four point drop in systolic blood pressure and a three point drop in diastolic blood pressure, but only if you have low blood levels of the nutrient. “It won’t help one bit if your levels are already within the target range,” said Thomas.

She compares the threshold effect to a roller coaster ride that has a height limit. There is no fun (nutritional benefit) until you are tall enough to ride, but after that getting taller doesn’t make it any more fun. At some point, if you get too tall it just gets risky and you’d better duck.

Thomas states there are several cases when a supplement may be beneficial:

  • Oregonians in general need vitamin D supplements from October through April.
  • Strict vegans who eat no meat, eggs or dairy need a source of vitamin B12 from a supplement or fortified foods. Vegetarians often need B12 supplements as do people taking daily heartburn medications and/or those over 60 years old.
  • Pregnant women have specific nutritional needs including iron, folate, choline and omega-3 fats, needs that often require supplements to achieve. Some nutrients must be present at time of conception, before you even know you’re pregnant. Serious birth defects can be prevented when multivitamins with folic acid and choline are taken by those who can become pregnant. New research suggests prenatal folic acid may reduce the risk of autism as well.
  • If you avoid fish, you need one to two fish oil pills a day to meet normal nutrition requirements for omega-3 fat. Higher amounts are helpful and prescribed for some psychiatric disorders.
  • Young children and pre-menopausal women should work with their health care provider to monitor iron levels in the blood. Iron needs are so high in these groups that the need for an iron supplement is common. Being low increases the risk of anemia, poor brain development, lead poisoning, poor pregnancy outcomes, and can affect mood and mental functioning.
  • People who have had bariatric surgery must take supplements every day for the rest of their lives or risk severe nutrient deficiencies including damage to the brain and nerve function.

Those who are under a physician’s care should always follow their physician’s advice regarding supplements. A registered dietitian can help assess your food and supplements in light of your health issues and advise you on ways to improve food choices and supplement safely as needed.

Choosing Safe Supplements

If you need a supplement, selecting the right one is important. Thomas encourages people to follow these guidelines when choosing:

  • Take the supplements you need. If your health care provider has recommended a supplement for you, be sure and take it.
  • Always buy quality. Stick to USP, NSF, CL or “approved” supplements.
  • Be even more cautious about herbal supplements. According to Thomas, 40 percent have quality problems and even good quality herbs can interact dangerously with prescription medications.
  • More is not better. Stick to 100 percent DV unless you get professional guidance.

Find out the three supplements Thomas recommends especially for Oregonians.
Learn more about eating to prevent cancer

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