Q: I've heard that food labels identify foods that are good
sources of different nutrients. How should this information be
used?
A: In the ``Nutrition Facts'' panel on food labels, the far
right column identifies a ``% Daily Value'' for most nutrients
listed. The Daily Value for a nutrient is the amount that could
reasonably be found in a healthy diet of an average adult. A food
supplying 10 percent or more of Daily Value is a significant source
of that nutrient, and at 20 percent or more of Daily Value, that
food contains quite a lot of that nutrient. Note that a high
percentage of Daily Value can be desirable, as in seeing that a
glass of orange juice is high in vitamin C, or less desirable, as
in seeing that a serving of regular canned soup provides more than
a third of the recommended sodium limit for a whole day.
A food supplying less than 5 percent of Daily Value of a
substance is really supplying a negligible amount. So although you
may be concerned to see a source of fat on the ingredients list, or
a high-fiber ingredient that you think sounds desirable, if the fat
or fiber are listed as less than 5 percent, the amounts consumed
won't do you much harm or provide much benefit unless you eat quite
a lot of the food each day.
Q: Does caffeine affect blood sugar levels?
A: Research suggests that caffeine can affect blood glucose
levels. Whether taken in coffee, soda, or certain over-the-counter
medications, the caffeine equivalent of two to three cups of
regular coffee raises the level of certain hormones known as the
``fight or flight'' hormones. These hormones keep blood glucose
levels up to provide energy for the fight or the flight that would
have protected us at some earlier evolutionary stage.
In one recent study, giving subjects caffeine produced blood
glucose levels higher than normally expected in the second and
third hours after consuming carbohydrate. People with diabetes
whose blood glucose levels are already too high should consider
whether caffeine may be contributing to their elevated glucose
levels.
Q: Are sprouts as nutritious as everyone says they are?
A: Sprouts, which are simply germinated seeds and beans, include
the common alfalfa and mung bean sprouts, but also sprouts of
broccoli, radish, soybean, pumpkin and others. Most sprouts are low
in calories (less than 30 calories in one cup), although soybean
and wheat sprouts are higher. In one-cup servings, all are good
sources of vitamin C, and some are good sources of the B vitamin
folate. Only mung bean sprouts contain a good amount of vitamin C
in smaller quarter-cup portions, however. Broccoli sprouts contain
high levels of sulforaphane, a phytochemical stimulator of the
body's own enzymes that detoxify carcinogens (cancer-causing
substances).
In the last few years, however, bacterial contamination of seeds
used in sprouting (mainly alfalfa sprouts) has caused food-borne
illness in nearly 1,000 Americans. The Food and Drug Administration
and the Centers for Disease Control and Prevention warn that people
with weaker immune systems (children, the elderly, those with HIV
or diabetes) should avoid alfalfa sprouts until safety improves.
All sprouts should be rinsed thoroughly with water, without soap or
detergent.
