Arizona Republic, AZ
09-12-06
We need that fat
A little bit helps us absorb the good stuff in fruits, veggies, studies find
Connie Midey
The Arizona Republic
You've dutifully upped your intake of vegetables and fruits, finding more ways
than you imagined possible to sneak broccoli, spinach and pink grapefruit into
your day's meals and snacks.
But before you rest on your laurels, consider a piece of the eating equation that
could be foiling your good intentions: Without adequate fat in your diet, your body
won't derive maximum benefit from those nutrient- and compound-rich foods.
"The real health enthusiasts, the ones who really cut back on the fat in their diet,
find that, in a sense, it's actually counterproductive," says researcher Wendy
White, an associate professor of food science and human nutrition at Iowa
State University.
She was prompted to study the issue by just such an enthusiast, a Procter &
Gamble supervisor whose staff of scientists took the question to White after
observing their boss eat large green salads with fat-free dressing almost every
day.
In the study that followed, White found that essentially no carotenoids were
absorbed when participants ate salads of spinach, romaine lettuce, cherry
tomatoes and carrots topped with a fat-free Italian dressing.
Antioxidant, disease-fighting carotenoids, the compounds that give red, yellow,
orange and dark green vegetables and fruits their color, are fat-soluble. That
means they need fat in order to be absorbed by the digestive system.
Absorption was greatest when White's test subjects ate salads with 28 grams
(almost one ounce) of canola oil, she says.
But even six grams promoted "significant" absorption of the carotenoids
lycopene, alpha-carotene and beta-carotene, compounds believed to help protect
against heart disease, certain cancers and other chronic illnesses.
Researchers at Ohio State University saw similar results when they added
avocados, which are rich in healthful monounsaturated fats, to mixed salads and
tomato-based salsas.
"It surprised us," says researcher Steven Schwartz, a professor of food science
and technology at OSU. "Absorption of carotenoids increased five to seven times
with the addition of avocado, which is amazing."
Carotenoids tested in the study were lycopene, beta-carotene and lutein, a
compound associated with improved eye health. As a bonus, the avocado added
nutritional benefits of its own, Schwartz says, including fiber, potassium and
vitamin C.
Researchers still aren't certain of the time frame required for best absorption. For
example, will coffee with full-fat milk an hour after a fat-free breakfast work?
Probably not. Preliminary conclusions suggest fat should be consumed in the
same meal as the vegetables or fruit, White says.
Nor are researchers sure how much fat per meal or snack produces adequate
absorption. The OSU study used about 10 grams in each serving, Schwartz
says, "and that could be high. Some people say you may need only three to five
grams."
Iowa State's White cautions that study findings "are not a license to whip out the
blue cheese salad dressing."
It isn't often, after all, that people eat salads or other fruits and vegetables in the
absence of a fat-containing food, she says.
A high-fat diet contributes to weight gain, heart disease and other health
problems. So she aims for a moderate six grams of healthful fats from canola oil,
olive oil, reduced-fat cheese, seeds, nuts or avocado with a meal, plus the
government-recommended five to nine servings of vegetables and fruit each day.
"Then even if you're not absorbing maximally every time," she says, "you still will
have the blood levels of carotenoids that have been associated with protection
against chronic disease."
Healthful ways to add fat to your daily diet
In the real world, you probably won't experience many occasions when
consuming too little fat is a problem.
But for the times you do, simple changes like these to a day's worth of meals and
snacks can help you increase absorption of fat-soluble nutrients from vegetables
and fruits while keeping fat intake at moderate levels.
Breakfast: Old-fashioned oats with non-fat milk, cantaloupe and pink-grapefruit
juice.
Add: Whole-wheat toast with one-half tablespoon trans fat-free canola margarine
for about 7 grams fat and 35 calories.
Bonus: By concentrating on good fats such as canola and avoiding unhealthful
trans fat, you're helping keep cholesterol in check.
Snack: Baby carrots.
Add: Two tablespoons hummus dip for 4.5 grams fat and 80 calories. Or one
tablespoon ranch dressing for 7 grams fat and 70 calories.
Bonus: Hummus also provides protein and fiber, plus a little iron, calcium and
vitamin C.
Lunch: Vegetable salad.
Add: One ounce avocado (two to three thin slices or 2 tablespoons) for 4 grams
fat and 45 calories. Or a half-ounce sunflower seed kernels for 7 grams fat and
80 calories.
Bonus: Avocado is high in healthful monounsaturated fat, has no cholesterol and
is a good source of fiber and vitamins C, K and folate. Sunflower seeds are rich
in vitamin E and have no cholesterol.
Snack: Apple slices.
Add: Spread slices with one tablespoon peanut butter for 8 grams fat and 105
calories. Or eat with one ounce reduced-fat string cheese for 2.5 grams fat and
60 calories.
Bonus: Peanut butter is cholesterol-free and provides fiber, protein, niacin and
manganese. Cheese is a good source of protein and calcium; try the reduced-fat
kind.
Dinner: Grilled skinless chicken breast, sweet potato, green beans, tomato slices,
diced fresh papaya and guava.
Add: Drizzle vegetables with 2 tablespoons sun-dried tomato salad dressing for 5
grams fat and 60 calories. Or stir the fruit into 8 ounces plain low-fat yogurt for 4
grams fat and 143 calories.
Bonus: Salad dressings made of olive or canola oil, which are mostly
monounsaturated fat, help to lower LDL cholesterol (the bad kind) and are a
good source of vitamin E.
Sources: Researchers Steven Schwartz of Ohio State University and Wendy
White of Iowa State University and Republic research
Reach the reporter at connie.midey@arizonarepublic.com or (602) 444-8120.