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A taste for fat? Mar 15, 2010, 11:12 am.

It turns out that humans have a taste receptor for fat–similar to the sensors that detect sweet, sour, salty, and bitter tastes.  According to a new published study, this sensor responds to the presence of fatty acids in foods. I'm guessing that this is what we sense when a food tastes "rich." However, people's sensitivity to this taste varies. A dish may be palatable to one taster but "too rich" for another.  Not surprisingly, people who are more sensitive to fats tend to eat fewer fatty foods and to weigh less. 

Although the study did not address this, researchers wonder whether a high fat diet eventually causes us to lose our "fat sensitivity," leading us to consume more fat and gain weight? It's not hard to imagine this.  People who eat a lot of salty foods develop a higher tolerance for salt; people who use artificial sweeteners (which are hyper-sweet) develop a higher tolerance for sweetness. 

The good news is that  when you start cutting back on salt and sugar in your diet, your sensitivity to these tastes also tends to return. After a period of adjustment, people often find that they need less salt to make foods taste well-seasoned, for example. And perhaps this means that cutting back on fatty foods would restore our sensitivity to them–and re-calibrate our appetite for them?

Here's another interesting tidbit:  Tasters detected linoleic acid (an omega-6 polyunsaturate) at lower levels than they detected oleic acid (a monounsaturate). The highest detection threshold was for lauric (a saturated fat).  Does that suggest that it's easier to overeat saturated fats? 

This research is too preliminary to draw any real conclusions but it's thought-provoking, isn't it? Hopefully, it provokes more research as well.

Summary of research

Study abstract

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Fresh vegetables? Think again. Mar 09, 2010, 5:12 pm.

What could be more nutritious than fresh vegetables? Frozen ones, quite possibly.

A new study finds that frozen vegetables, which are usually processed within hours of being harvested, may contain more of certain nutrients than “fresh” vegetables, which may be weeks old by the time they’re consumed. This latest study was funded by Birds-eye, but it’s actually nothing we didn’t already know. According to the USDA, fresh vegetables can lose up to 50% of their nutritional value after just one or two days of room temperature storage or one to two weeks of cold storage. 

This is not a nutritional emergency. Even at half strength, vegetables are still among the most nutritious foods you can choose. And many valuable nutrients, such as fiber, minerals, and fat-soluble vitamins like E and K, are fairly stable in storage. In other words, the kale that’s been sitting in my fridge since last weekend’s shopping trip is still going to make a great, nutritious side dish for tonight’s dinner.

But the study is a good reminder. Scoring extra-fresh produce from the garden or farmer’s market is a good way to maximize the nutritional value–but eating it promptly is just as important. And if you are stocking up for more than a week or so at a time, frozen veggies may be the best bet for long storage.

Note that the nutrient values for fresh produce you see here on Nutrition Data (which are taken from the USDA’s nutrient database) reflect samples found in typical grocery markets around the country.

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How safe is imported fish? Mar 05, 2010, 1:06 pm.

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Balancing a high sodium diet Mar 02, 2010, 11:13 am.

Q.  I’m a college student and while I definitely focus on maintaining a balanced diet I am concerned about my sodium intake.  With the amount of processed foods in the school cafeteria, it’s almost impossible to maintain a low sodium diet.  I’m healthy and active with a normal blood pressure and I’ve always considered sodium the least worrisome of the food evils (though high blood pressure does run in my family). My personal assumption has always been that as long as I increase my water intake along with sodium, everything will “balance out” in the body.  Is there any truth to this? If so, how much water is necessary to offset 2400 mg sodium over the recommended daily value?

A. First, I congratulate you for making nutrition a priority!  Secondly, I sympathize with your challenge of limiting sodium when faced with typical cafeteria food. Thirdly, I agree that because you are healthy, active, and have normal blood pressure, you may not need to worry too much about some extra sodium in your diet.

As for “balancing” the sodium intake, drinking more water will help mitigate excess water retention due to the high sodium diet. (Ironic, but true.)  How much water it takes depends on all kinds of variables: your activity level, temperature and humidity of your environment, and so on. As a general rule, if you are urinating several times a day and your urine is pale in color, you are adequately hydrated. Keep in mind, however, that certain drugs and vitamin supplements can color the urine.

Many people also believe that increasing potassium is a good idea when sodium intake is high. See this post for more on that.

Finally, a couple of suggestions on how to keep your sodium intake sane, despite the challenges you describe.

1. Salad bar!  Most cafeterias offer a salad bar and here, at least, the vegetables are not likely to be drenched in salt.  As a bonus, vegetables are a great source of potassium and water!  Watch out for salty add-ons like bacon, sunflower seeds, olives, three-bean salad, and mixed dressings.  Most salad bars include cruets of oil and vinegar…use those for your dressing.

2. Say no to avoidable salt.  You may have to live with  a certain amount of sodium in the prepared foods in the cafeteria. But you can opt out of salty but nutritionally empty foods like chips and French fries, right?

3. Campaign for change!  Talk to the cafeteria manager (or your student life rep or the school newspaper editor…) and ask if the food service can pay more attention to offering lower sodium options. With the huge public debate going on right now over reducing sodium intake, they should be a little more tuned in to your concern.

Hang in there!  You’ll soon have more control over your food choices and it sounds as if you are motivated to make good ones.

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