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Too little salt can be a problem, too

Mar 17, 2010, 10:52 am.

Q. When I was younger I remember seeing a salt pill dispenser next to a
drinking fountain at a military base. I was told that they were there
because when you work hard and sweat a lot your body needs more salt. I
realize that most people probably get more salt than they need, but do
we lose a significant amount of salt during a workout?

A. With all the hoopla about reducing everyone's sodium intake lately, it's probably a good time to mention that too little salt can be just as big a problem as too much.

The salt pills at the military base were to prevent hyponatremia (low blood sodium). When exercising for long periods of time or in very hot conditions, sodium losses through sweat can be profound. If blood sodium dips too low, you can experience dizziness, vomiting, loss of consciousness, progressing to seizures, coma, and death. Sodium imbalance caused by profuse or extended sweating can be exacerbated by drinking large amounts of water.

Every year, a handful of marathon runners and long-distance hikers collapse due to hyponatremia. Tragically, some have died because medical professionals mistook the symptoms for dehydration and administered fluids…which made the condition worse. Fortunately, a growing awareness of hyponatremia has reduced sports-related hyponatremia fatalities.

I don't want to scare people unnecessarily: Short exercise bouts are unlikely to be a problem. The conditions you want to be careful of are extended exertion (3 plus hours) and extremely hot temperatures, which increase sweat output.

While it's important to stay hydrated in these conditions, you also need to be careful to replace sodium and other electrolytes as well. Electrolyte drinks such as Gatorade may not be enough to maintain sodium balance during extended exercise in hot weather. In these cases, salty foods or salt pills can be a lifesaver.

For more information:

Hyponatremia (Mayo Clinic)

Guidance for Athletes (American College of Sports Medicine)

Salt and the Endurance Athlete (Rice University)

Potassium for muscle cramps? Not necessarily

Mar 08, 2010, 10:01 am.

Q. I am on high blood pressure meds and have noticed a lot of cramping in my legs. How much potassium in mgs should I be taking a day?

A. The Institute of Medicine established 4.7 grams (4700 mg) of potassium as the adequate intake (AI) for most healthy people. The average American gets between 2300 mg (women) and 3100 mg (men) from their diet. However, I wouldn't recommend that you start taking potassium supplements.

First of all, the general recommendation may or may not be appropriate for you. Some high blood pressure meds can increase potassium requirements, others can cause high potassium levels.

Secondly, I wouldn't assume that the cramps are caused by a lack of potassium. Imbalances in potassium, sodium, and/or magnesium can all lead to muscle cramps and any of these is a distinct possibility when someone is taking high blood pressure medications.

I strongly recommend that you report the muscle cramping to your physician (who knows what drugs you're taking) and ask for guidance. He or she can test your electrolyte levels to see what's really going on. The solution to the cramping might involve a change in medication, diet or lifestyle changes, or nutritional supplements. But this is not a time to do-it-yourself.

Will you keep us posted?

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How safe is imported fish?

Mar 05, 2010, 1:06 pm.

Q. Is imported frozen fish from countries like India and Vietnam safe? I
avoid buying any food imported from China but I bought frozen Swai Basa Fish (farmed) from Vietnam and frozen Squid
(caught wild) from India. They tasted really good and they were cheap,
but I’m wondering if we can trust those imports or they may be full of
some toxic stuff.

A. Theoretically, the safety of fish being sold in U.S. markets is monitored by federal agencies such as the FDA, whose job it is to be sure that the fish sold for human consumption in the U.S is “”safe, wholesome, and not misbranded or deceptively packaged.” (Institute of Medicine on Seafood Safety)

But as we’ve seen lately, the ability of the FDA to effectively police the food supply and enforce its regulations is in serious doubt. Just a few years ago, for example, there was a scandal in which salmon being sold for a premium as “wild-caught” in both wholesale and retail markets turned out to be cheap farmed salmon. ( Story from New York Times)

To make things even more challenging, fishing and farming practices are changing rapidly around the globe as demand for seafood increases. New restrictions and best practices are being implemented. But loopholes and work-arounds are also constantly being discovered and exploited. It’s a moving target!

The best resource I’ve found to keep up with these issues is Seafood Watch. These guys are working hard to stay on top of all of these issues and to provide up-to-date resources for consumers trying to make safe and responsible choices. They have a number of tools for consumers, including a mobile app for your smart phone or a low-tech wallet card, as well as in-depth reports.

I scanned Seafood Watch’s reports on both the fish you mentioned. In terms of toxins or contaminants, I didn’t see too much to worry about with the wild-caught squid, but these comments on farmed swai basa got my attention:

“Commercial aquaculture for finfish in Viet Nam continues to use relatively low technology and many operations continue to use homemade feeds…[with] little or no management of aquaculture operations…”

The safety of these fish as food obviously depends primarily on the water they’re raised in and the food they are fed. They might be perfectly fine, but it doesn’t look as if anyone is paying too much attention.

From a sustainability perspective, which is more about the long-term health of the oceans than the safety of the food, both wild-caught squid and farmed swai basa are considered “good alternatives” but not “best choices.”

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Why can’t I search for foods low in choline?

Mar 04, 2010, 11:03 am.

Q, I need to find foods that are low in choline but in the Nutrient Search tool, I can only search for foods highest in choline. Is there any way to do this?

A. The reason you're running into this is that choline hasn't been measured in all foods. The USDA has focused on evaluating foods that are thought to be significant sources of choline. So, to present a list of foods that are "lowest in choline" would be a little misleading. Only the foods that have been measured for choline can be included in the results and these foods will probably be higher in choline than
many other foods that haven't been measured. Make sense?

The USDA has published an extensive report on choline which you can access here. In that report, they have the following helpful table, which gives you an idea where most of the choline in your diet is found. As you can see, eggs (specifically, the yolks) are by far the most significant source of choline. Hope that helps!