Weight Loss & Diet Plans

The Down Low on Low-Carb Diets

Low Carbs and Supplements

The lower your intake of carbohydrates, the greater your need for a vitamin supplement. That's the mantra that most doctors now recommend that everyone on a low-carb diet should never forget.

The reason? Any time you restrict your diet, particularly in terms of certain food groups, your nutrient levels can drop. But when your diet is low carb, experts say you may be in even greater need for certain key vitamins and minerals, particularly folic acid.

"If you're cutting out cereals, fruits, vegetables, fortified grains, then you are cutting out your major source of folic acid, a B vitamin that is not only important when you are pregnant, but important to everyone's overall health," says NYU nutritionist Samantha Heller.
What's more, says Heller, folic acid is key to controlling levels of homocysteine, an inflammatory factor linked to heart disease. If you're already at risk for cardiovascular problems, she says, dropping folic acid levels too low could put your health at serious risk.

One way to protect yourself, she says, is to take a B vitamin supplement -- with at least 400 micrograms of folic acid daily.

"All of the B vitamins work together in a very complicated metabolic pathway and they need each other -- so if you are not going to get your source in foods, then a vitamin supplement is a must," says Heller.

Sondike agrees and says that, "Any time you are on a weight-loss diet you need a good multivitamin, regardless of whether you are limiting your carbohydrate intake or not," he says.

Although there has been some evidence that a low-carb diet can also take its toll on calcium levels, Sondike says that fortunately, this is usually only on a short-term basis.

"Your body will often shift metabolism when you do something different to it -- but it equalizes -- you see a rapid shift and a return to normal -- and the longer-term studies show normal results in this area," says Sondike. Still, he tells WebMD it's a "smart idea" to take a calcium supplement beginning at the start of your low-carb diet to safeguard against a possible deficiency. Tofu can also be a good source of calcium.

Another mineral you may want to supplement is potassium. While there is no concrete evidence that a dramatic potassium loss occurs on a low-carb regimen, Sondike says to ensure against problems he recommends patients use Morton's Light Salt -- a potassium chloride product that he says can add back any of this important mineral that's lost. Eating a few almonds is also a good way to supplement this mineral without adding carbs to your diet.

Finally, if you stick to your low-carb diet via the use of prepackaged foods, experts say read the label carefully to avoid ingredients that are notoriously responsible for gastrointestinal upsets, and especially excess gas. Among the worst offenders: sugar alcohol, found in sweeteners such as sorbitol.