How much Vitamin D is Safe?

Q. I’ve read a lot about the health benefits of Vitamin D. But isn’t there also a limit of how much Vitamin D I should supplement? Is there a danger or limit that avoids a possible toxic amount?

A. The Institute of Medicine recently doubled the safe upper limit (UL) for vitamin D from 2000 IU to 4000 IU. That’s still quite a bit lower than the 10,000+ IU a day that some vitamin D researchers recommend. The IOM tends to be rather conservative and research suggests that 10,000 IU a day is unlikely to cause problems.  But I think the IOM may be trying to provide a counter-balance to what some see as “irrational exuberance” being displayed by some vitamin D aficionados. Continue reading “How much Vitamin D is Safe?” >

Ask Monica: Your Nutrition Questions Answered

Have a food or nutrition-related question for me? I’m happy to help. Actually, chances are pretty good that someone has asked a similar question already, so you might want to search first. [wp_google_searchbox]

If you don’t find what you’re looking for, feel free to contact me using the form below.  Although I can’t give individual medical or nutrition advice over the internet, I’ll try to point you in the right direction.

I often answer questions in my newsletter. Leave the box at the bottom of the page checked to be sure to get it.

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Do water filters remove valuable minerals?

Q. In your podcast on mineral water, you said that tap water can be a source of minerals such as calcium and magnesium.  If I use a water filtration pitcher to filter my tap water, am I removing these nutrients?

A. Great question!  To answer it, I got in touch with both PUR and Brita, who manufacture water filtration pitchers. Both assured me that any calcium or magnesium that is in your tap water to start with will not be removed by the filtration process.

Trying to eat more veggies? Don’t forget about sea vegetables!

Trying to get more vegetables into your diet but getting bored with broccoli and spinach? There’s a whole category of super-nutritious vegetables you may be overlooking. Sea vegetables, otherwise known as seaweed, are a great way to add variety to your five-a-day routine. You can add sea vegetables to soups or stir-fries or make a seaweed salad instead of the same old tossed salad. You can even use seaweed to make nutritious—and addictive—chips to snack on.

This article is also available as a podcast. Click to listen

What Kinds of Seaweed are Good to Eat?

As with land vegetables, there are lots of different kinds of sea vegetables, with various flavors and textures. Some are soft, others are chewy; some are mild, others very briny.  Here’s a brief guide to some common sea vegetables.

What Are the Different Types of Sea Vegetables?

Alaria is harvested in the Atlantic and is a distant cousin of Japanese wakame. It has a fairly pronounced briney flavor and a chewy, slightly rubbery texture.

Arame is a delicately textured plant that grows wild off the coast of Japan. It has a soft texture and bland flavor that reminds me of very thin cooked buckwheat noodles.

Dulce, with its broad, reddish-brown fronds, is harvested off the Atlantic coast of Maine. It has a medium strong, somewhat smoky flavor.

Hijiki is a dark, small-leaved seaweed from Japan that resembles dried tobacco. It has a tender-crisp texture and a very mild, almost sweet flavor.

Kombu, or kelp, is a broad-leafed variety that grows wild in the very northernmost region of Japan’s Arctic sea. It’s often used in stocks or ground as a flavor enhancer.

Wakame is a tender, dark-green seaweed that is harvested in Japan. It has a mild flavor and a texture similar to cooked spinach.

What are the Nutritional Benefits of Seaweed?

The nutritional profile of different types of seaweed varies as well. In general, sea vegetables are low in calories and contain a variety of minerals including calcium, magnesium, and potassium. Dulce and alaria, are quite high in iron and vitamin B12, which makes them particularly good choices for vegans who may otherwise have difficulty getting these nutrients.

Some—but not all—types of seaweed are high in sodium. For example, alaria and wakame are both high in sodium, but arame and hijiki are quite low.

Can You Get Too Much Iodine from Seaweed?

Most types of seaweed also contain iodine, a nutrient that’s important for healthy thyroid and neurological function.  Iodized salt is the primary source of iodine in American diets. If you use a natural sea salt instead of iodized salt, including seaweed in your diet can be a good way to be sure you’re getting enough of this important nutrient. But more is not always better. Although iodine is needed for healthy thyroid function, too much iodine can also interfere with your thyroid.

A serving or two per day of seaweed won’t cause a problem for most people. But just to be on the safe side, I suggest avoid eating large amounts of seaweed every single day, particularly kombu or hijiki, which are particularly high in iodine. Dried kelp granules, which are often sold as a salt substitute, are also a potent source of iodine. A quarter teaspoon can provide two or three times the suggested upper limit for iodine intake, so you don’t want to overdo that either.

Where Can You Buy Seaweed?

Dehydrated seaweed is the easiest to find. You may find one or two types in the international aisle of your local grocery store. You’ll probably find a larger selection at a health food store or a natural foods grocer. The best prices and selection are usually found at Asian groceries or markets, where they might even have fresh or frozen seaweed, which is otherwise fairly hard to find. If you’re having trouble finding a good selection, you can also shop online from the sources listed below in the Resources section. Keep a few packages of dried seaweed on hand for those times when you run out of fresh vegetables and don’t have time to make it to the market.

How Do You Prepare Seaweed?

Many dehydrated sea vegetables are ready to use in salads, soups, or stir-fries after a brief soak in cool water; others need to be boiled for a few minutes. Soaking seaweed in water is also a way to reduce the sodium content, although you may end up losing some of the other minerals as well.

Some varieties don’t even need to be rehydrated. For example, dehydrated dulce can be eaten right out of the bag—it tastes sort of like jerky. Or, sauté pieces of dulce in a bit of olive oil until they’re crisp. You can eat it instead of chips, use it in place of the bacon in a BLT, or crumble it over a baked potato.

This article was originally published on QuickandDirtyTips.com

How safe is imported fish?

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.

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.”

How healthy is 100% fruit juice, really?

Q. What should I look for when buying fruit juice? For example the “100% pure and natural orange juice” says it contains 0% Vitamin C. How is that possible? Another one provides 100% Vitamin C but from the list of ingredients we see that Vitamin C is actually added.

A. The USDA considers a half cup of fruit juice equivalent to a serving of fruit but I have my doubts.  Processed fruit juice–even 100% juice–is a distant second to fresh whole fruit in terms of its nutritional value.

For one thing, fruit juice is a very concentrated source of sugar and calories. All the fiber, which slows the absorption of the sugars in whole fruit, has been removed.

Secondly, many (most?) of the naturally-occurring nutrients are lost during processing, pasteurization, and storage.  As you found, manufacturers may compensate for this by adding nutrients back to the juice after the fact.  You could get the same benefit from taking a vitamin C capsule.

Nutritionally, I’d rank processed fruit juice only slightly higher than soda and other sweetened beverages.

If you choose to drink fruit juice, consume it in moderation. Freshly-prepared juice (made from whole fruit with a juicer and consumed immediately) preserves more of the antioxidants. But for the full nutritional benefits of fruit, I think you’d be far better off consuming whole fresh fruit–and drinking water!

Lard vs shortening?

Q. I am attempting to cook this recipe I found on the internet. It calls for 1/4 cup of lard OR vegetable shortening. I am health-conscious and I was wondering which option is healthier?

A.   If the vegetable shortening contains hydrogenated or inter-esterified oils, I’d say go with the lard–unless you’re a vegan, of course.

Lard has a bad reputation that I’m not sure it deserves. Like most animal fats, lard contains a mixture of saturated, monounsaturated, and polyunsaturated fats.  In fact, it contains more monounsaturated fats (13mg per ounce) than saturated fats (11g per ounce).   It also provides 280mg of omega-3 fatty acids per ounce.

If you’re looking for a vegetarian option, see if you can find a shortening that combines coconut or palm-kernel oil with unhydrogenated vegetable oil.  Both coconut and palm-kernel oil contain saturated fats, which allow them to stay solid at room temperature. In baked goods, that is often key to getting the right texture.

But straight coconut or palm kernel oil might not produce the best results. Unlike lard, coconut and palm kernel oil are almost 100% saturated fat. At room temperature, they are the consistency of candle wax! To produce something similar to shortening, manufacturers blend them with liquid (unsaturated) oil.

See also: On lard, pie crusts, and whether all saturated fats are the same

Purslane as a source of omega-3: a reality check

Purslane has gained a reputation as being a good source of omega-3 fatty acids. An oft-cited 1992 analysis, published in the Journal of the American College of Nutrition, found that 100 grams of purslane contained 300-400 mg of omega-3 fats.

But if you search the scientific literature, you’ll see that the amount of omega-3 fats in purslane varies a LOT, depending on the variety, the age of the plant, the part of the plant you analyze (leaves, stems, seeds), and the time of harvest. The purslane analyzed in the 1992 study was clearly at the high end of the range.

Is purslane a valuable source of omega-3 or not?

It’s true that, compared to other green vegetables, purslane is rich in omega-3 fatty acids. About half the fat in purslane is omega-3. But green vegetables are very low in fat, so that doesn’t add up to much.

Let me put this in perspective for you: Even if you were lucky enough to got some high octane purslane like the stuff analyzed by Simopoulos in 1992, you’d need to eat 4 pounds of it to get the amount of ALA found in one tablespoon of flaxseed oil.  Hope you’re hungry!