I read some years ago
that one of the “biomarkers”
aging was tolerance to
hot and cold temperatures. I
no longer hear about that, and
wonder if this is still considered
an important indicator?
Answer : You’re recalling the book Biomarkers: The
10 Determinants of Aging You Can Control
by Tufts’ William Evans, PhD, and Irwin H.
Rosenberg, MD. Dr. Rosenberg, who is the editor
of the Health & Nutrition Letter, says, “Yes,
we still consider that exercise enhances the
capacity for thermoregulation, which declines
somewhat with age. As an older person, you
have a reduced sensation of thirst and a lessened
ability to sweat and shiver. While exercise
probably won’t alter your thirst mechanism
for the better, it may still reduce your risk
for dehydration injuries. Staying in shape, no
matter what your age, helps you adjust to the
heat.” That’s because people who exercise have
higher total body water content, sweat more
when they work out in the heat, and lose fewer
Before cooking steel-cut
oats, I grind them for
30 seconds until they
get to a flour-like consistency.
Am I losing nutrition
by doing this? And would I be
better off nutritionally by cooking
rolled oats instead?
Answer : We checked with our recipe editor,
Patsy Jamieson, who replies: “When you
grind the oats, you retain the fiber and
phytonutrients in the oats, but the porridge
will not be as beneficial for your blood sugar
because the glycemic index (the measure
of how quickly a carbohydrate affects blood
sugar) is higher. The smaller the particle size
of a grain, the higher the glycemic index. Steelcut
oats have a relatively low glycemic index
of 42. When you grind the oats, the glycemic
index increases. I did not find a glycemic index
value for oat flour (probably because it is not
commonly consumed as a porridge), but for
comparison purposes, the glycemic index of
rolled oats is 55. Instant oatmeal has a glycemic
index value of 83.”
Jamieson developed a steel-cut oatmeal
porridge recipe for our January 2012 newsletter.
To get around the long cooking time of
steel-cut oats, she found that soaking the oats
in cold water overnight reduced actual cooking
time to 10-15 minutes.
After being diagnosed with atrial fibrillation, I was put on warfarin, a blood thinner. Now I am supposed to avoid all those nutritious dark-green leafy vegetables I used to eat, like spinach, Swiss chard and beet greens, because they are high in vitamin K, which helps the blood to clot. But I am missing out on all their other healthy nutrients. Is there a way around this dilemma?
ASarah Booth, PhD, director of Tufts’ HNRCA Vitamin K Laboratory, replies, "I would recommend that you work with your healthcare provider to have green vegetables in your diet that contain healthy nutrients but may not have the high amount and variability in content of vitamin K that the greens listed have. Paler leaves and other green plant-based products, such as peas, are still healthy but are not so rich in vitamin K. Also, there are ways to have modest amounts of those high vitamin K greens in the diet, hence not complete avoidance. Clearly the days of spinach salads are over for you, but substitutions can be made, including some raw spinach in combination with other plant-based foods. Perhaps consultation with a registered dietitian (RD) would benefit you, along with consistency of diet, careful monitoring and lots of communication with your healthcare provider."
Should Atlantic sardines
be avoided in favor
of Pacific sardines?
If so, why?
Answer : The choice of
comes from concerns about the health of the
oceans, rather than the health of consumers.
The Monterey Bay Aquarium Seafood Watch
advises avoiding Atlantic sardines for now
because “these fish come from sources that
are overfished or fished or farmed in ways that
harm the environment.… Many populations
of Atlantic sardines in the Mediterranean are
declining due to overfishing. This, and ineffective
fishery management, result in an ‘Avoid’
ranking.” Instead, Seafood Watch suggests,
choose Pacific sardines from US waters, rated
a “Best Choice”: “These fish are abundant, well
managed and fished or farmed in environmentally
The Environmental Defense Fund www.edf.org adds that Pacific sardines are low
in contaminants and high in heart-healthy
omega-3 fatty acids: “Adults and children can
safely eat more than four meals per month”
containing these fish.
I’m a 70-year-old male whose usual exercise is weight training with relatively heavy-duty intensity and consistency. I started taking a whey protein supplement to meet my protein needs. Is it better to take with meals or at more times throughout
Roger A. Fielding, PhD, director of Tufts’ HNRCA Nutrition, Exercise, Physiology and Sarcopenia (NEPS) Laboratory, answers, "To enhance the effects of the whey protein it is better to take after exercise and between meals so it does not act as an appetite suppressant and decrease your usual food intake."
Fielding and colleagues have recently studied whether added protein, such as that in whey supplements, could help protect against sarcopenia, the gradual loss of skeletal muscle in the later years of life. Researchers compared the effects of a whey-protein beverage (40 grams/day)against a placebo in a group of men and women ages 70-85 who also underwent resistance strength training. The study concluded that whey-protein supplementation at this dose did not offer additional
benefit in mobility-limited older adults.
Whey protein is a collection of proteins isolated from whey, a byproduct of cheese manufactured from cow’s milk.
Is there any food value left in the parboiling water used to blanch vegetables before freezing?
Could it be used as a nutritious tea or added to soups? Seems like a waste to throw it away.
A Natalie Faella, a dietetic intern at Tufts’ Frances Stern Nutrition Center, answers: “I agree, it does seem like a waste to just toss the water left over after boiling vegetables. It has been shown that nutrients in the vegetables are lost during different cooking methods such as boiling in water. In particular, it is the water-soluble vitamins like vitamin C and the B vitamins that leach out the most from vegetables into the water. Therefore,
the water actually does have some nutrient value after the vegetables have been cooked in it. This water can be saved and used in soups, stews, sauces, gravies, etc., to salvage those nutrients that would be otherwise lost.
“It is recommended to refrigerate this water in an airtight container until used (which should be within a few days to receive maximum nutritional value). Another helpful tip would be to use as little water as possible when boiling the vegetables, so it will be easier to incorporate into another dish.
“When cooking vegetables, as opposed to parboiling for freezing, simmering the vegetables
(first bringing the water to a boil, then lowering the heat before adding the vegetables) and steaming are better options for preserving the nutrient content. A study published in the Journal of Zhejiang University Science reported that steaming vegetables resulted in the least amount of vitamin C, cholorphyll, glucosinolate and protein losses when compared to other cooking methods.”
Is there any value to drinking cactus juice?
There may be benefits to consuming cactus—
which is, after all, a plant—and people have been eating prickly pear cactus pads and syrup for centuries. But the evidence for the specific
health claims typically made for products containing cactus juice (and other ingredients) is scant. Naturally occurring compounds in cactus called betalains are said to reduce inflammation. The literature on the health benefits of cactus betalains is very limited, cautions Jeffrey B. Blumberg, PhD, director of Tufts’ HNRCA Antioxidant
Nutrition Laboratory. Most studies cited supporting the benefits of products containing cactus juice were conducted in vitro (“test tube” laboratory experiments) or on rats and mice. The primary human study actually focused on curing hangovers; possible anti-inflammatory benefits were inferred as an explanation for the “moderate
effect on reducing hangover symptoms.”
If you don’t have a family history of breast cancer,
do the cardiovascular benefits of drinking red wine outweigh the cancer risks from alcohol consumption?
Answer : AJoel B. Mason, MD, Tufts professor of medicine
and nutrition and director of the HNRCA Vitamins & Carcinogenesis Laboratory, replies: “In general, the increased risk of cancer associated
with alcoholic beverages is observed only when habitual consumption exceeds levels of moderate consumption. Moderate drinking is defined as an average of two drinks a day for men and one drink a day for women. A drink is defined as 12 ounces (355 milliliters, or mL) of beer, 5 ounces (148 mL) of wine or 1.5 ounces (44 mL) of 80-proof distilled spirits. On the other hand, the purported benefits of red wine on cardiovascular health are observed within these limits of moderate consumption. Therefore, if red wine consumption remains within these guidelines
one might realize a benefit to heart health without invoking any additional risk of cancer.”
I will use blood thinners the rest of my life, and so watch out for foods high in vitamin K. I’m aware of leafy greens, but are there other fruits and vegetables I should be cautious about?
Sarah L Booth, PhD, director of Tufts’ HNRCA Vitamin K Laboratory, answers, “Blood thinners
are among the top 15 drugs prescribed in this country, and adverse drug events for these drugs account for some staggering numbers among the elderly.” People who have been prescribed warfarin, the most common such anticoagulant medication, need to monitor their vitamin K intake because warfarin works by affecting
the body’s vitamin K. But Booth goes on, “Although vitamin K is found in numerous green fruits and vegetables, one would have to eat very large amounts to achieve high intakes. Examples would be green peas and kiwi fruits. Most of the vitamin K is in the peel of fruits, such as apples. One popular food item that is appearing more often on the shelves that may be of concern is some of the green seaweed, especially if consumed
in large amounts.”
Do apples lose any nutritional benefits when cooked?
A Diane McKay, PhD, a scientist in Tufts’ HNRCA Antioxidant Nutrition Laboratory,
answers: “Like most foods, cooking apples will tend to decrease the vitamin C content, since this nutrient is particularly susceptible to heat. If cooked with the skins on (like baked apples), you can retain most of the fiber and some of the phytochemicals.
Since the fiber is primarily found in the skins, if you peel them, as you would to make applesauce, you remove most of the fiber.”