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Zinc and iron--two important minerals that can be tough to get enough of, especially if you don't eat meat. Part of the problem is that grains and legumes contain a compound called phytic acid that blocks the uptake of minerals from these foods. But researchers have found that the sulfuric compounds found in garlic and onions appears to help "unlock" these minerals and enhance your ability to absorb them.
According to this research, adding a clove of garlic or a quarter of an onion per serving of rice or legumes can double your nutrient take-away! Here a few yummy, seasonal options that fit the bill:
Warm Herbed Coriander Rice Salad
Q. I'm wondering if my body is able to average out my weekly nutrient intakes as easily as my nutrition calculator can. For example, if I get an entire week's worth of vitamin K from a single kale salad on Sunday, is that vitamin K really doing me any good by the time Saturday rolls around, or did my body flush out all that extra K before I went to bed on Sunday? Are some nutrients stored up and time-released better than others?
[Answer updated 7/7/2010]
A. Some nutrients ARE stored better than others. In general, fat-soluble nutrients--which include A, D, E, and beta-carotene--are stored in the liver and fatty tissues of the body, so you don't need to consume them every day. Liver stores of vitamin D help get you through the shorter days of winter, for example, when your skin isn't able to manufacture enough vitamin D.
Water-soluble nutrients, such as vitamin C and the B family of vitamins, aren't stored in the body, so you need a steady supply of these.
Vitamin K is a bit of an exception (as pointed out by well-informed readers of this blog). Although it is a fat-soluble nutrient, the vitamin K from foods is not very efficiently absorbed or stored. However, the amount that is absorbed is conserved or "recycled" for further use. Vitamin K is also synthesized by beneficial bacteria in the but on an ongoing basis. Vitamin K deficiency in adults is uncommon.
It's okay if your intake of most fat-soluble vitamins goes up and down from day to day, as long as it averages out to the recommended amount over the course of a week or so. But you want to hit the recommended target for water-soluble vitamins on a daily basis.I'd love to try your recipe kale salad. I'm always looking for new ways to enjoy this super-nutritious vegetable. Care to share it?
Q. I eat a lot of cold water fish such as herring and sardines for their
healthy fat profile, but am often very surprised by their high
saturated fat levels. For example,a can of Crown Prince Natural brisbane sardines in water has 17g of fat, 8g of sat fat and 2g omega-3. Is the saturated
fat in fish any different or better than the saturated fat in a hamburger?
A. It's true that fish (like all animal flesh) contains some saturated fat. In the listing for sardines here on ND, only about 15% of the fat is saturated, while about 50% of the fat in the Crown Prince brand is saturated. Both brands contain about the same amount of omega-3s. Frankly, I'm not sure why that brand has such a different fat profile.
But as for the saturated fat itself, it is chemically very similar to the saturated fat that you find in a hamburger. About half is in the form of palmitic acid, about a quarter is stearic acid, and about a tenth is myristic acid. So, to answer your question, the saturated fat in fish really isn't any different or better than the saturated fat in a hamburger. The biggest difference, in terms of your heart, is that the fish also comes with a nice helping of omega-3s!
Of course, there's a massive debate going on right now over whether we even need to worry about saturated fat. See my post "Is Saturated Fat Back on the Hook?" Nonetheless, if the high saturated fat content of the Crown Prince sardines concerns you, you might want to look around for another brand. I checked several other brands at my local grocery store and most of them were lower in fat overall, with a much lower proportion of saturated fat.
Q. How do we determine the energy content of a food ? For instance, how do we know that 200g of beef provides roughly 350Kcal ?
A. A popular project for high school science fairs is building a calorimeter--a device that measures the energy in foods or other objects. You build a combustion chamber in which you can burn a piece of food. The heat (energy) generated is transferred to a chamber containing water. By measuring the difference in the temperature of the water, you can calculate how many calories the food contained.
But calorimeters overstate the amount of energy that you actually get out of your food. Due to the vagaries of digestion and absorption, you capture only a percentage of the energy that food contains. Fiber, for example, can be burned to produce heat in a calorimeter, but can't be burned as food energy in the body.
So, calories in food are estimated a little differently. First, they're analyzed to determine how much water, fiber, protein, fat, alcohol, acetic acid, and carbohydrate they contain. Then, we calculate how many calories each of those components contributes, based on our knowledge of human energy metabolism and digestion. Finally, the numbers are added up for a fairly accurate estimate (but an estimate nonetheless) of how many kcals you're likely to get out of that 200g of beef!
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"Are organic foods less fattening than regular foods?" It seems like a silly question. Obviously, organic certification describes how foods are produced. It has nothing to do with how much fat, sugar, or calories a food contains. Yet consumers apparently think desserts are less fattening if they're organic, as demonstrated by a recent study at the University of Michigan.
Of course, we're all too smart for that, right? Actually, I suspect we're all a lot more susceptible to the "health halo effect" than we think. When we read about these studies, the subjects' responses seem naive and silly--but that's because we're in on the joke. Had we been the one in the hot seat--and not clued in to the point of the questions, a lot of us would probably reveal the same sort of unconscious bias. For more, see Junk Food in Disguise.
I'm sure there are many bariatric physicians and surgeons who treat their patients conscientiously and holistically. Unfortunately, gastric bypass surgery has become a cash cow for unscrupulous docs operating "drive-through" lap-band clinics--and the consequences can be fatal.
Gastric bypass is a highly effective way to promote weight loss. Unfortunately, it's an equally effective way to create serious malnutrition. Because the amount of food you can eat and your ability to digest and absorb nutrients are so drastically reduced after surgery, your diet after surgery must be very carefully managed--forever. But patients are being operated on and sent out the door with little more than one-sheet hand-out of vague dietary instructions and little meaningful follow-up.
This week's Archives of Internal Medicine details the case history of a woman who died of malnutrition six years after gastric bypass surgery. It makes me furious!!
Ideally, bariatric surgery would be used only as a last resort and only in conjunction with intensive nutritional, behavioral, and emotional counseling and support. It's time for the medical profession to step up and self-police. And for those considering gastric bypass, be sure you know what you're signing up for.
Any readers out there with experiences to share?
How ironic. Iodized salt was introduced in the 1920s as a way to prevent iodine deficiency. It worked! But now, the American Thyroid Association is worried that if the sodium police get their way and people really start cutting back on salt, thyroid problems and birth defects could be an unintended consequence.
Your body needs iodine in order to produce thyroid hormone. Iodine deficiency is especially dangerous (and especially common) during pregnancy, when it can cause problems with the infant's neural development and lead to mental retardation. Some researchers are investigating whether low iodine levels during pregnancy might increase the risk of ADHD.
Sodium is intake up but iodine intake is down
Iodized salt is the primary source of iodine in the American diet. But even though average salt consumption is twice the recommended level, iodine intake has actually declined about 50% over the last 30 years. How can that be? Well, we used to cook at home, using iodized salt. Today, most of the salt we consume comes from packaged and processed foods--which are not necessarily made with iodized salt.
As long as we're bossing around the food industry and requiring them to reduce the sodium in their products, perhaps we ought to require them to use iodized salt.
Alternate sources of iodine
In the meantime, if you don't use iodized salt at home (or you don't cook much), be sure you have an alternate source of iodine. Seafood and edible seaweeds, such as wakame, are particularly rich in iodine. You also get some iodine from vegetables, depending on the iodine content of the soil in which it is grown. According to the Linus Pauling Institute, iodine is added to feed for dairy cows in the U.S., which makes dairy products a fairly good source of iodine.
Even though iodine intake has declined, most people are still getting the recommended amount. But if you are pregnant (or planning on it) a multivitamin with the daily recommended amount of iodine (150 mcg) would be a good back-up.
A. The short answer is "No." But I think you may be confusing a couple of different issues here.
Grass-fed meat may or may not be raised organically. And organically-raised cows may be grazed on pasture or fed (organic) grain. Unless the meat is certified organic, it's likely that the cows were given antibiotics--regardless of whether they were grass-fed or fattened on grain.
Even if the animals are given antibiotics, however, the antibiotics are not going to be present in the meat itself. The problem with agricultural use of antibiotics is not that the antibiotics remain in the meat--it's that they breed antibiotic-resistant bacteria.
For more on why it's very important to restrict the use of antibiotics in livestock, please check out this episode of my weekly Nutrition Diva podcast: Antibiotics in Meat.
A. I agree with you. There's no medical reason to eat cookies after giving blood--and a few reasons not to!
Here are some tips on what to eat before and after giving blood, which should help prevent any wooziness.
1. Don't give blood when you're very hungry. Try to schedule your donation so that you can eat a healthy meal no more than 4 hours beforehand.
2. Don't donate blood if you are eating a very low-calorie diet for weight loss. If you're dieting, ease up a bit and eat slightly larger portions of protein foods and vegetables the day before and of your donation.
3. Immediately afterward, a piece of fruit or small cup of yogurt would provide some easily digested sugars to keep blood sugar from dipping--and be a healthier choice than cookes. Prunes or prune juice are high in iron (see #5 below) and would be a particularly good choice.
4. Drink plenty of water before and after donating blood to replace those fluids. (Blood is mostly water).
5. Make sure to eat foods that are high in iron in the days before and after donating blood. The form of iron in meat, poultry, and fish is the best absorbed. If you're a vegetarian, prunes, prune juice, and blackstrap molasses are all good sources of iron.
(Our nutrient search tool can help you find more foods high in iron.)
Finally, take it easy for a minutes before rushing back into your routine after donating blood and avoid strenuous exercise for several hours after giving blood.
*Donating blood saves lives and supplies are often critically short. To donate blood, visit:
The National Blood Service (U.K.)
For other locations, Google "donate blood <country>"
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