Category: Nutrition in the News

My take on the latest diet and nutrition headlines.

How safe is imported food?

by Monica Reinagel, MS, LDN

I was just reading a very interesting article on the safety of imported foods. Unfortunately, the publication (ADA Times) is for members of the American Dietetic Association so I can’t post a link for you. But here are a few nuggets you might like to know (with thanks to managing editor Liz Spittler, who researched and wrote the article).

Nearly 1/5 of the overall American food supply (and 80% of the seafood we eat) is imported. This represents a massive increase. While inspectors used to handle a million “entry reviews” a year, the number now approaches 25 million.  In response, the FDA is modernizing its oversight systems, including a new computerized screening process that helps inspectors zero in on the imports that are most likely to be a problem.  The FDA has also opened offices in five countries overseas in order to increase oversight and American food safety experts are training foreign food processors on the latest food safety techniques.

Continue reading “How safe is imported food?” >

How much Vitamin D is Safe?

by Monica Reinagel, MS, LDN

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?” >

Evidence against BPA is stacking up

by Monica Reinagel, MS, LDN

As consumers have grown increasingly worried about the potential harm from BPA in plastic water bottles and canned food, food manufacturers have mounted a massive campaign aimed at convincing us that we’re over-reacting. See for example this article from the industry-funded International Food and Information Council: Science and the BPA Controversy

But it’s getting harder and harder to claim that consumers have nothing to fear from “normal” BPA exposure. New data out of Italy links BPA from foods to changes in testosterone levels. These are not lab rats being given huge doses of BPA. These are humans, simply going about their normal lives and eating their usual diet. Continue reading “Evidence against BPA is stacking up” >

How much sunshine do you need to get your Vitamin D?

by Monica Reinagel, MS, LDN

 

UPDATE: September 2024: There are now a couple of smart-phone apps that are MUCH easier to use than the cool but somewhat clumsy calculator described in my original post!! 

DMinder (iOS/Android)

Vitamin D and UV Tracker (Android)

SunDay Vitamin D and UV Tracker (iOS)

There’s been a lot of hand-wringing lately about people not getting enough vitamin D.  Deficiency is quite common–especially among kids, the elderly, and those with dark skin. And a growing list of diseases and conditions are being linked with vitamin D deficiency. (See also Your Brain on Vitamin D)

Exposure to the sun, without sunscreen, causes your skin to produce vitamin D naturally.

How much sun does it take to satisfy your vitamin D requirements?

If you’ve read anything about this, you’ve probably seen some vague guidelines, recommending “a few minutes every day.” But these recommendations are far too general to be useful. The amount of sun you need to meet your vitamin D requirements varies hugely depending on your location, your skin type, the time of year, the time of day, and even the atmospheric conditions.

A Cool Tool: The vitamin D/UV calculator

Scientists at the Norwegian Institute for Air Research have devised a calculator that will take all those factors into consideration and estimate how many minutes of exposure you need for your skin to produce 25 mcg (the equivalent of 1,000 International Units) of vitamin D.

It’s a very cool tool and the best I’ve seen so far. Be forewarned: It’s not the most user-friendly interface and its very easy to enter the wrong information, which makes your results misleading. But once you get past the technicalities, it’s very interesting to see how much the answers change when you vary the input.

Here are some tips to help you get good results

1. Unless you live in one of a few European or African cities listed as options, you’ll need to determine your latitude and longitude.  A GPS device will tell you your lat/long. You can also find this information here.  VERY IMPORTANT: The program reads all latitudes as N and all longitudes as E. If your latitude is 39 S, enter -39.  If your longitude is 76 W, enter -76. (It took me forever to figure out this quirk!) Also, be sure to click the radio button next to your latitude and longitude entries. It is not automatically selected when you fill in these values.

2. You also need to estimate your complexion, and the options include both “blond” and “pale,” which is a little confusing. (Maybe it makes more sense to Norwegians.) Basically, the six categories are arranged from lightest (pale) to darkest (black).  Make your best guess based on that. I have dark eyes and hair so I chose “darker caucasian.”

3. Enter the time of day you are going out in the sun, expressed as UTC (aka Greenwich Mean Time).  Here is a converter that will convert local time into UTC. The calculator uses a 24 hour clock, so hours from 1pm to midnight are expressed as 13 to 24.  There is also an option that lets you choose “about midday.”  If you enter an actual time, be sure to click the radio button next to your start time. It doesn’t move automatically when you fill in these values.

4. Next, enter how much cloud cover there is.  If you choose “overcast,” you can also enter in the UV Index from your local newspaper’s weather page and the program will estimate the thickness of the cloud deck. Again, be sure to click the radio button if you choose this option. (Disclaimer: I played around with this and couldn’t see that changing the UV index had any effect…)

5. You’re almost done! Next, the calculator wants to know the thickness of the ozone layer. I have to admit, I was unable to find a simple resource to help with this one.  Unless you live under the ozone hole or have some other way of knowing that the ozone is particularly thick or thin where you are, I suggest just setting this one to medium.

6. Find your altitude. Some GPS devices can tell you your altitude, as can Google Earth or topographical maps. But the easiest way may be to simply google “altitude of [your town]”. Remember to convert it to kilometers.  One kilometer = about 3300 feet.

7. Choose your surface.

Here’s what my form looks like all filled in:

UVcalc.jpg

When I submit it for calculation, I learn that here in Baltimore, on a cloudless July day at noon, I need to spend just 5 minutes with my face, hands, and arms exposed to produce 25 mcg (1,000 IU) of vitamin D.  If it were November, I’d need to stay out about half an hour. If it were November, and I were black, it would take an hour and a half. You get the idea.  For most of the year, “a few minutes” of sun would not be enough for me to make enough vitamin D.

Keep in mind that these exposure times are considered enough to maintain healthy vitamin D status. if you are starting out with a vitamin D deficiency, you might need more.

One last thought: Unprotected sun exposure also increases the risk of skin cancer and premature aging of the skin. After you’ve gotten your daily “dose,” I recommend applying a good sunscreen!

Your Brain on Vitamin D

by Monica Reinagel, MS, LDN

brain.jpgOur collective crush on Vitamin D shows no sign of tapering off.  Researchers just published new results from a 6-year study showing that seniors with low vitamin D levels are 60% more likely to suffer from substantial cognitive decline than those with adequate levels of the nutrients, raising “important new possibilities for treatment and prevention.” (Archives of Internal Medicine.)

Vitamin D supplementation is presumably what they’re talking about. (Is there anyone left out there that’s NOT taking vitamin D?)

But brain aging seems to be a very difficult nut to crack.  One by one, other “important new possibilities for treatment and prevention” of cognitive decline have failed to pan out:  Fish oil, crossword puzzles, exercise, ginkgo biloba…despite high hopes, none turned out to make a significant difference.

Will vitamin D be the breakthrough we’ve all been hoping for?

Could raising low blood levels with supplements do the trick or is there something about the lifestyle of people with higher vitamin D levels that’s helping them stay healthier? Maybe higher vitamin D levels indicate that they spend more time outdoors; perhaps it’s a marker for people who are more active? Or simply healthier?

We’re all so enamored of vitamin D right now, it’s hard to be objective. But, as Tim Byers points out in an editorial for the American Journal of Epidemiology, we’ve been similarly enthralled (and ultimately disillusioned) with other nutrients in the past.  (Anticancer Vitamins du Jour–The ABCED’s So Far.)

I don’t mean to be a Debbie Downer. For all of our sakes, I hope that vitamin D turns out to be the superstar that we hope it is. But, I wouldn’t be surprised if we’re ultimately led back to the same conclusion: There’s just no way to put a healthy lifestyle, diet, and environment (plus good genes) into a pill.

Red meat and cancer: dumbing down the science

by Monica Reinagel, MS, LDN

At this morning’s session on Diet and Cancer, Dr. Marji McCullough gave an epidemilogist’s-eye view of the relationship between cancer and diet. Her main point was that focusing on overall dietary patterns (such as higher fruit and vegetable intake) rather than individual nutrients and foods (such as broccoli sprouts or soy) appears to be the most effective way to reduce cancer risk.

Throughout her talk, she was careful to point out the limitations of the research and how hard it is to collect and intepret data in the extremely messy experimental model known as “free living humans.”  So I was a little disappointed to hear her single out “red and processed meats” as one of the only food groups for which there is consistent evidence of a link with cancer.

First of all, it always irritates me to hear “red and processed meat” discussed as a single food group. My friends, there is a world of difference between a hot dog and a bison steak.

Cured meats and cancer

There does appear to be a link between cancer and high consumption of processed (i.e. cured) meats like hot dogs, sausages, salami, and cold cuts–most likely due to nitroasamines formed from the nitrates used to cure these meats. Incidentally, nitrosamines are deactivated by vitamin C and the link between cured meat consumption and cancer risk disappears in those who eat a lot of vegetables. That’s right: Those who eat the most cured meats but also the most vegetables have no increased risk of cancer.

But, I digress.  Back to (uncured) red meat.

Cooking methods and cancer

McCullough suggested that red meat consumption might contribute to cancer because heat-heat cooking methods (such as grilling) create harmful compounds. Hang on a minute. Maybe the problem isn’t red meat. Maybe the problem is charred meat.   After the talk, I had a chance to chat with Dr. McCullough and she admitted that from the existing data, most of which was collected 20 and 30 years ago, researchers can’t really distinguish between the type of meat and how it was cooked. Nor can they separate Big Macs from flank steak…nor beef from bison…nor grass-fed from corn-fed. It’s all just “red meat.” And what kind of red meat were Americans eating most of in the 80s and 90s?

Dumbing down the science?

For folks who eat most of their red meat in the form of char-grilled, high-fat, fast-food burgers, telling them that they can cut their cancer risk by cutting back on “red meat” may be good public health policy.  But in over-simplifying the prescription this way, we may be throwing the baby out with the bathwater.

Is there any evidence to suggest that lean, grass-fed red meat, prepared in a way that minimizes formation of HCAs and PAHs increases your risk of cancer? No, there is not. (Click for tips on how to reduce harmful compounds)  In fact, compared with poultry, red meat is higher in monounsaturated fats and lower in omega-6 fats–two qualities that red meat has in common with the cancer-protective Mediterranean diet pattern.

Industry opposes BPA ban (of course)

by Monica Reinagel, MS, LDN

I hate to be cynical but I think I can see where this is going.

A food safety bill with broad bipartisan support and poised to become law is suddenly being opposed by food industry and business groups. Why? Because of a recently added amendment to ban BPA from food packaging. (More from the Washington Post)

Food packagers think we should wait two more years for the FDA to complete its investigation before deciding whether or not to remove BPA from the food supply. They argue that the evidence against BPA is based on a small number of flawed, biased studies.  Read more from the International Food Information Council.

Consumer advocates and health researchers argue that when there is as much reasonable cause for concern as there is for BPA, the substance should not be “innocent until proven guilty” but rather “off the shelf until proven innocent.”

Should the food industry control food safety legislation? Of course not.  Yet I predict the amendment will ultimately be removed.  But perhaps this is something the market can take care of for itself.

Consumer concern over high fructose corn syrup has led manufacturers to begin removing HFCS from their products and replacing it with cane sugar.  (Personally, I don’t think this accomplishes very much but that’s a different post.) Some manufacturers are similarly responding to the BPA concern with BPA-free packaging.  And whether or not the amendment goes through, a lot of consumers are already voting with their dollars.

See also: BPA: Which foods are safe?

Fructose: Poison, Nutrient, or Both?

by Monica Reinagel, MS, LDN

Given the escalating rhetoric on fructose, I think it’s time to revisit a couple of basic facts and try to regain some perspective.

Fructose is not a toxin. It is not a man-made “chemical.” The fact that is it metabolized in the liver does not mean that it is a poison.

Fructose is a naturally occurring mono-saccharide (sugar) found in fruits, vegetables, nuts, grains, eggs, dairy products and other whole foods. It has been part of the human diet since the beginning. Presumably, our bodies are well-adapted to it.  In fact, there might be an evolutionary advantage to the ability to metabolize sugars through multiple pathways–including one that does not lead to an immediate rise in blood sugar.

All nutrients are potentially toxic

As the National Academy of Sciences states: “All nutrients can have adverse effects when intakes are excessive.”  That’s why tolerable upper limits (ULs) have been established for many nutrients. The NAS recommends that you don’t exceed 45mg per day of iron, for example. But no-one is suggesting that iron is a poison or that it should be avoided at all costs. Maybe if we had a tolerable upper limit for fructose, we could all relax a little bit.

How much fructose is too much?

According to a recent analysis, Americans are now consuming somewhere between 38 and 73g of fructose a day. A third of that comes from sweetened beverages. The rest comes from other processed foods as well as grains, fruits, vegetables, eggs, cheese, and other whole foods.

It seems clear that current sugar intake is excessive and making us sick. Many argue that it’s fructose, specifically, that’s doing most of the damage. Fine: For the sake of argument, let’s just say that the current average intake of 55g of fructose (or around 10% of total calories) is enough to overload the liver and contribute to obesity and other ills. That suggests that somewhere between 0 and 55g per day is a threshold at which fructose ceases to be a useful (or at least harmless) nutrient and starts to be a problem.

Seeing as it doesn’t seem possible, necessary, or even desirable to reduce fructose consumption to zero, I think it would be useful to start looking for that threshold.

What is the tolerable upper limit for fructose?