Nutrition Hotline
By Reed Mangels, PhD, RD
QUESTION: “I'm a registered dietitian working with the WIC Program (the Special Supplemental Nutrition Program for Women, Infants, and Children). WIC is finally giving soy milk and tofu to pregnant, breastfeeding, and postpartum women and their children. On one website, I found dire warnings that tofu has to be steamed for at least five minutes (if not baked or fried) to kill bacteria. Does this ring true?” C.P., MD
ANSWER: Heat treatment of tofu is usually not necessary, but you present a special situation. Pregnant women, babies, and young children, as well as other people with immature or compromised immune system function, are at a higher risk for food-borne illness. For these groups, it's best to be careful — tofu being eaten raw (tofu salad, smoothies, etc.) should be steamed for 5-10 minutes and then cooled before use. Chances are low that someone would have ill effects from tofu that has been kept refrigerated, sealed, and used before the expiration date, but because this is a vulnerable population, I'd err on the side of caution. Rinsing tofu before cooking it is another step that can be helpful to reduce the amount of surface bacteria.
It isn't necessary to steam aseptically packaged tofu (like Mori-Nu). It has been heat-treated so as to be shelf-stable, and this heat treatment destroys bacteria. Aseptically packaged silken tofu has a consistency that works well in dishes where the tofu is not cooked, such as salad dressings, dips, and blended drinks. If steaming seems cumbersome, using aseptically packaged tofu that doesn't need to be steamed simplifies meal preparation.
QUESTION: “I'm taking a drug called warfarin to prevent blood clots. My doctor asked if I drank cranberry juice or ate spinach. Why would she ask this?” A.M., FL
ANSWER: Warfarin is sometimes called a blood thinner, although it really doesn't make your blood thinner. It does make your blood less likely to clot, something that's important if you're at risk for a stroke or other problems.
To do this, warfarin keeps your body from making clotting factors. Vitamin K also plays a role in blood clotting. If your vitamin K intake varies a lot from one day to the next, it can interfere with what warfarin does. This doesn't mean that you should completely avoid foods that are high in vitamin K, such as spinach, but you should eat approximately the same small amount of those foods daily — not a lot one day and none the next. Other foods high in vitamin K include broccoli, Brussels sprouts, chard, collards, kale, mustard greens, parsley, and green tea.
Cranberries, cranberry juice, and other cranberry products can also interfere with warfarin, as can many herbal products. Ask your doctor or registered dietitian about which foods you should limit. Be sure to tell him or her about any herbal supplements that you take, and don't make changes in your diet without discussing them with your doctor.
QUESTION: “I read that eating a pound of meat provides more calories and nutrients than does a pound of grain. Is this true?” N.P., via e-mail
ANSWER: This does seem like a strange comparison. Realistically, we do not eat solely meat or solely grains. If the intent is to compare non-vegetarian and vegetarian diets, using grains as a point of comparison seems odd since vegetarian diets also include beans, vegetables, fruits, nuts, and possibly dairy products and eggs.
First, let's look at whether the statement “a pound of meat provides more calories than does a pound of grain” is accurate. As the table below shows, this may or may not be true, depending on the type and cooked state of each product.
| Calories Per Pound | |
| Brown rice, cooked | 504 |
| Brown rice, raw | 1,680 |
| Wheat flour | 1,544 |
| Oats, raw | 1,721 |
| Oats, cooked | 322 |
| Ground round, broiled | 1,135 |
| Beef round, raw | 808 |
| Roast beef, cooked | 903 |
Source: U.S. Department of Agriculture, Agricultural Research Service. 2010. USDA National Nutrient Database for Standard Reference, Release 23. Nutrient Data Laboratory Home Page, <www.ars.usda.gov/nutrientdata>.
So, a pound of meat may provide more or fewer calories than a pound of grain.
What about the statement that “a pound of meat provides more nutrients than a pound of grain?” To illustrate this statement's false nature, the next table shows the amount of iron in a pound of grain versus a pound of meat.
| Milligrams of Iron Per Pound | |
| Brown rice, cooked | 1.91 |
| Brown rice, raw | 6.67 |
| Wheat flour, enriched | 21.07 |
| Wheat germ | 41.27 |
| Quinoa (grain), raw | 20.75 |
| Ground round, broiled | 11.8 |
| Beef round, raw | 8.72 |
| Roast beef, cooked | 10.58 |
Source: U.S. Department of Agriculture, Agricultural Research Service. 2010. USDA National Nutrient Database for Standard Reference, Release 23. Nutrient Data Laboratory Home Page, <www.ars.usda.gov/nutrientdata>.
Similar results are seen when we look at niacin levels of meat versus grains.
| Milligrams of Niacin (Vitamin B3) Per Pound | |
| Brown rice, cooked | 6.937 |
| Brown rice, raw | 23.113 |
| Wheat flour | 22.505 |
| Wheat germ | 25.379 |
| Ground round, broiled | 24.416 |
| Beef round, raw | 30.781 |
| Roast beef, cooked | 22.836 |
Source: U.S. Department of Agriculture, Agricultural Research Service. 2010. USDA National Nutrient Database for Standard Reference, Release 23. Nutrient Data Laboratory Home Page, <www.ars.usda.gov/nutrientdata>.
Based on these charts, we can safely say that the nutrient and calorie content of a pound of meat and a pound of grain vary widely and that we cannot say that either is higher or lower in calories and nutrients.
