Is taking fish oil environmentally irresponsible?

In a paper published in a Canadian medical journal last week, researchers argue that the benefits of taking fish oil are not well enough substantiated to justify its widespread use. The authors are concerned that the growing demand for fish oil will deplete fish populations.

Not well enough substantiated?  That's pretty hard to fathom.  The evidence linking the consumption of oily fish or fish oil supplements with improved cardiovascular and brain health is over-whelming.  Compelling enough to cause the American Heart Association and the National Academies of Science (among others) to revise their nutritional guidelines to include specific recommendations for Omega-3 intake.  It's also fairly clear that plant sources of omega-3 fatty acids, while beneficial, are not as biologically active as the longer-chain fatty acids found in fish body oils.

Good for us, bad for the planet?

But what about the sustainability question?  This is far muddier than the issue of whether taking fish oil is beneficial to the general population. Fisheries around the world are certainly facing great pressures due to increased demand. Questions over whether increased (or even current) production is sustainable are very real. 

The race is on to develop more sustainable sources of long-chain omega-3s.  We already have algae-produced DHA and algae-produced EPA is hopefully not far behind. This advance would allow us to produce vegan omega-3 supplements that contained the more potent long-chain fatty acids without using any fish.

But consider this very interesting and cogent observation made by fatty acid researcher William Lands: the demand for omega-3 supplements would be much lower if we were to reduce our intake of omega-6 fats, found in corn and other vegetables oils and abundant in processed and packaged foods.

Current recommendations for omega-3 intake are based on the amount of omega-3 fats needed to balance our intake of omega-6 fats. (The ratio of these two fats in the diet is at least as important as the absolute amounts.)  Lands points out that, "If we just lowered the current flood of omega-6 fats, sustainable amounts of omega-3 fats could manage our health.”   

If you'd like to read more about this issue, Here's a summary and interview with the authors from Science Daily.  By way of rebuttal, check out this article by Craig Weatherby. Keep in mind, however, that Craig works for Vital Seafood, a company that sells fish and fish oil (albeit with an admirable commitment to environmental sustainability). 

Obviously, it's a complex issue. I'm interested to hear your thoughts! Personally, I think Dr. Land's advice makes a lot of sense.  Sometimes, less is more.

How do I convert recipe measurements into grams or ounces?

Q.  Most of my recipes give the ingredients in cups, teaspoons, and tablespoons, not grams or ounces. But when analyzing recipes on ND, I can't always find the measurements I need. For example, I wanted to add 1/3 cup of dried egg whites to a recipe but my only options were grams or ounces. How do I convert these measurements ?

A. We have a conversion tool, which you'll find on the right hand side of the page. For example, the conversion tool will convert grams to ounces or tell you how many tablespoons are in a cup.

As handy as this is, it wouldn't have helped you here, though. The conversion tool will only convert weight measurements to other weight measurements (such as grams to ounces) or volume measurements to other volume measurements (such as cups to gallons).    But it will not convert a volume measurement (such as 1/3 of a cup) to weight (grams or ounces).

There’s no way to do that because weight and volume are not a constant relationship. A cup of water weighs 237 grams but the same volume of raisins weighs only 145 grams.

Every food in our database is analyzed by weight, so all foods are listed in 100-gram and 1-ounce serving sizes. For many foods, such as the raisins shown below, the USDA also provides a variety of volume-related meaures (and their weight equivalents), as well. This comes in very  handy when analyzing recipes. 

Unfortunately, the ingredient you were looking for (dried egg whites) is only listed in grams or ounces. In this case, check the nutrition facts label on the package of the food you are using. At the right, you'll see the nutrition facts label for some dried egg whites I found, indicating that 2 tablespoons equals 14 grams.  (That may vary from product to product, depending on the texture of the powder.)

So, if you added 6 tablespoons of these dried egg whites (which  is a little more than a third of a cup) to your recipe, you would add 42 grams (or 1.5 ounces) to your recipe analysis!

Sodium and Potassium: What's the relationship?

Q. Please comment on the relationship between potassium and sodium.  How can I be sure that I'm not getting too much potassium as I continue to decrease the amount of sodium in my daily diet? 

A.  Decreasing the amount of sodium in your diet won't necessarily affect the amount of potassium you're getting but it will probably increase the ratio of potassium to sodium in your diet--and many believe that this is a good thing!

Sodium and potassium have complementary functions in the body, helping to regulate things like fluid balance and blood pressure.  We need to maintain a precise balance of potassium and sodium in our cells but our intake of potassium and sodium may vary greatly from day to day. Therefore, the body has systems that tightly regulate this balance, excreting any excesses into the urine.

The potassium/sodium content of our modern diet is radically different than the diet our ancestors ate--and many believe that this contributes to a lot of our modern health problems. Potassium is found in fruits and vegetables; most of the sodium we eat comes from processed and packaged foods.

By some estimates, our ancestral (pre-industrial) diet had a potassium to sodium ratio of at least 3:1, meaning that it contained about three times as much potassium as sodium.  However, as we've come to eat more and more processed foods and less fruits and vegetables, our intake of potassium has declined and our intake of sodium has skyrocketed.  The typical potassium to sodium ratio today is 1:3 (three times as much sodium as potassium) or exactly the inverse of our ancestral diet.

Whether or not the potassium/sodium ratio theory is correct, reducing your intake of processed foods and increasing your intake of fruits and vegetables is a great health upgrade for your diet!  I think  its pretty unlikely that you will get too much potassium from foods. Most Americans get about 2500 to 3000 milligrams per day; the recommended intake is about twice that!

Seasonal Vegetables: Spring cleaning for the body?

Q. Taught by my grandmother, I practice the time-honored tradition of eating a lot of the spring greens that are starting to come out: dandelions, burdock, stinging nettles, pigweed, lamb’s quarters, plantain, shepherd’s purse, garlic mustard, chickweed, cleavers, and so on. What does modern nutrition have to say about this? Are these greens truly "blood cleansing" or "liver cleansing?"

A. In traditional Chinese acupuncture, each season is associated with a different organ and spring is the season of the liver. Many other traditional and alternative healing systems teach that certain plants "cleanse" or "strengthen" the blood or other organs.  You won't find too much about that in Western nutrition science, though.

The greens you mention here are all highly nutritious, bursting with antioxidants and folic acid, nutrients that support healthy organ and immune function. Some spring vegetables (in particular, dandelion greens and asparagus) are also diuretics, which can help rid the body of excess fluids. Although it might seem like foods that make you pee more might be "cleansing" your kidneys, these foods simply increase the amount of sodium and water that is excreted in the urine.

Your body's detoxification pathways work year-round to break down and remove toxins and impurities from your blood and tissues.  Eating a lot of fresh vegetables (and cutting back on sugar, alcohol, sugar, and other junk food) is good for your whole body and supports all your organs but, in my opinion, your organs don't need or benefit from seasonal "cleansing."

In your grandmother's day, green vegetables (other than cabbages, which store well for the winter) may have been few and far between during the winter months. By the time early spring greens arrived, people's nutrient reserves were running low and their bodies were hungry for the nutrients in these vegetables.  It was smart to making the most of spring's nutritional bonanza. That's less likely to be the case nowadays, when finding a green salad in January is as easy as heading to the nearest grocery store.

But I still  love the idea of eating with the seasons because it means that the foods you're eating are fresher and at their nutritional peak.  Eating foods grown close to where you live also reduces the carbon footprint of your diet.   So, even if they aren't doing anything special to "cleanse" your blood, eating fresh spring greens is a great move for your health.

Adventures with Odd Vegetables: Sunchokes

Where I live in the mid-Atlantic region, we're still a couple of weeks away from the first fresh vegetables of Spring. The early peas, asparagus, and baby lettuces should be showing up at the farmer's market around the beginning of April.

In the meantime, the farmers are bringing the last of their stored, winter vegetables; lots of turnips, winter carrots, potatoes, onions, and--this week--Jerusalem artichokes, also known as sunchokes.  Looking like a cross between a potato and a knob of ginger, sunchokes aren't even distantly related to artichokes. They are actually a member of the sunflower family. Their flesh is crisp, like a water chestnut, with a slightly, sweet nutty taste.

Sunchokes can be used in almost anything that you would normally use small potatoes in...you can boil and mash them or slice them and prepare like scalloped potatoes. A mixture of half potatoes and half sunchokes is particularly good.

They are also quite complementary nutritionally, as well. Potatoes are a good source of vitamin C and B6, while sunchokes are rich in thiamine and iron.

This morning, I made a delicious frittata by sauteeing sliced sunchokes in a bit of olive oil until they were the texture of cooked new potatoes--about 8 minutes. Then I added beaten eggs to the skillet and cooked over low heat without stirring for a few minutes until it was almost set. Finally, I grated some cheddar cheese over the top and ran it under the broiler until it was puffy and brown.  A new Spring favorite!

I found lots more recipes using Jerusalem artichokes from our sister site, Epicurious.com. This one, for Jerusalem Artichoke and Arugula Salad with Parmesan looked particularly good!

Do you have any favorite seasonal or unusual vegetables?

Weight fluctuations: How much is normal?

Q. I have heard that it is completely normal for a person's weight to vary throughout the day, but by how much does it change? Is it a sign of weight gain if I weigh over three pounds more at the end of a day than at the beginning?

A. A weight fluctuation of three to five pounds over the course of a day is completely normal and doesn't suggest that you've gained weight.  Weight can be temporarily affected by things like the amount of fluids you've consumed, the timing of your last work-out, or (how to put this?) the status of your digestive processes.

It's best to weigh yourself at the same time of day.  If you're in the habit of charting your weight, you might want to start plotting the moving average, as well.  A moving average is a statistical trick that smooths out those daily ups and downs and gives you a much more accurate picture of the overall trend: are you gaining, losing, or maintaining? 

I've been using this nifty little gadget called The Google 15.  Type in your weight every day and it is displayed on a graph.   After 7 days, the graph will also display your moving average. The gadget even gives you encouraging pats or stern little warnings if you drift too far from your goal.

If Google's pending domination of the universe gives you the creeps and you're good with math, here's the formula for calculating a simple moving average yourself. 

Online Surveys & Market Research

Is it okay to eat raw sweet potatoes?

Q. My husband and I have developed a taste for raw sweet potatoes.  We peel and slice them like carrots.  Is a raw sweet potato as nutritious as a cooked one?  Can the body digest and accept the vitamins and minerals as in a cooked sweet potato? Thanks for your help.

A.Raw sweet potatoes contain a chemical called trypsin inhibitor, which inhibits the activity of an enzyme that your body needs to digest protein.  The trypsin inhibitor in sweet potatoes is almost entirely inactivated when you cook them.

For that reason, eating large quantities of raw sweet potatoes on a regular basis might not be such a great idea. But small amounts of raw sweet potato (such as shredding a bit on top of a salad or eating a few raw sweet potato chips as a snack) probably will not cause any big problems.

Sweet potatoes (raw or cooked) are a great source of beta-carotene, which is a fat soluble vitamin. Eating them with something that contains a bit of fat will enhance your ability to absorb this nutrient.

What kind of milk is best for blood sugar control?

Q. I'm concerned with blood sugar control and am wondering what kind of milk (low-fat, whole, soy, almond, lactose-free, etc.) would be best to put on my breakfast cereal?

A.  If you're concerned with blood sugar control, you should get acquainted with the estimated glycemic load (eGL) tool here on Nutrition Data.  The eGL predicts how various foods affect your blood sugar. (You can read more about how the eGL is calculated on our eGL Help Page.)  As a general rule, a food with a lower eGL may be a better choice for blood sugar control.

Foods with an eGL of less than 10 are generally considered "low glycemic" and the eGL for 1 cup of whole milk is 9.  (Keep in mind that the eGL changes when you change the serving size. The eGL of TWO cups of milk would be 18.)

Interestingly, though, there isn't a whole lot of difference in the eGLs of various kinds of cow's milk.   Skim milk and lowfat milk, have the same eGL as whole milk.  This suggests that in terms of blood sugar control, it doesn't much matter which type of milk you choose. All of them are considered low glycemic foods. But whole milk has almost twice as many calories as skim milk, so if you're watching your weight, reduced fat milk might be the better option. 

I also looked up various kinds of soy milk.   Soymilk contains a bit of fiber, which would tend to lower the eGL but many varieties also contain added sugars, which raises the eGL.   Here's one variety with an eGL of 6.  But most clustered right around 8 or 9--virtually the same as cow's milk, and all in the "low-glycemic" category.  There was a big range in terms of fat and calories--so you'd want to take that into account as well.

Unfortunately, I did not find any listings for lactose-reduced milk or almond milk in our database. But you can calculate the eGL by entering the information on the Nutrition Facts label from the package into our Custom Entry tool and clicking "analyze."

Here's the bottom line: The eGL gives you helpful information about foods and how they are likely to affect blood sugar. But you may also want to pay attention to things like fat and calories. Diabetics who are counting carbohydrates might also want to take the number of carbohydrate grams into account.   

Eight weeks to a healthier heart: Meet our Heart Health Champion

I want to introduce you to a new friend of mine! Vanessa Bush is a 44-year old mother of two with a family history of heart disease.  Recently diagnosed with high cholesterol, Vanessa can see herself starting down a road that too many family members have already gone down. Instead, she's agreed to be our new Heart Health Champion.

"I don't want to inherit the health problems of my parents' and grandparents' generations," she writes. "I'm not currently taking medication for any health problems, and I don't want to start. So if there's something I can do right now to improve my chances of enjoying my life free of serious illness and disease, I want to be proactive. That's why I've decided to take the ND challenge."

Heart Health Champions: Beating heart disease with nutrition

Vanessa and I met recently to discuss her dietary patterns and identified some areas that could use improvement. We also talked about the the things that make it challenging for her to eat right and exercise. (I think you'll find them familiar.) For the next eight weeks, we'll be working on strategies to make her diet and lifestyle heart-healthier, with the goal of reducing Vanessa's risk factors for heart disease.

You can follow Vanessa's progress on our Heart Health Champion page. She'll be tracking her diet, using our tracking tools, and blogging about her efforts. We'll be offering expert advice along the way. You can support Vanessa with your comments and input, as well. Or, better yet, join us in this eight-week journey to a healthier heart. You'll find all the tools you need to get started in our Heart Health Resource Center. 

Should B12 fortification be mandatory?

A series of articles and letters to the editor in this month's American Journal of Clinical Nutrition asks whether the time has come to mandate the fortification of flour with B12, similar to the mandatory fortification with folic acid.

Apparently, the call for B12 fortification has been gaining momentum in recent years. But I would think that fortification of the food supply would only be warranted in the case of widespread inadequacy. However, the number of people affected by B12 deficiency is relatively small. B12 deficiency is most common among the elderly, due to diminished absorption of the nutrient. Yet only about 6% of people over 60 are deficient.

B12 deficiency is more common in developing nations, where animal protein may be scarce. But these populations would probably not benefit from fortifying American processed food with B12.

There are also questions about whether the elderly most at risk of B12 deficiency would benefit from fortification programs.  Although there don't seem to be any serious risks associated with B12 fortification, I'm not yet convinced that it's a good idea. What do you think?

From the American Journal of Clinical Nutrition:
Is it time for vitamin B-12 fortification? What are the questions?
How common is B12 deficiency?