ST. LOUIS - Most women know that calcium is critical in preventing osteoporosis, the disease of progressive bone loss and fractures that affects millions of Americans.

But which source is better — calcium-rich foods or supplements? A preliminary study by researchers at Washington University School of Medicine suggests dietary calcium may be better at protecting bone health.

Though not definitive, the study found that women who get most of their daily calcium from food have healthier bones and higher bone density than women whose calcium comes mainly from supplemental tablets.

That was true even though the supplement-takers had higher average levels of calcium.

Calcium from dietary sources is generally better absorbed than that from supplements, which could help explain the difference, said the study's lead author, Dr. Reina Armamento-Villareal.

Those getting calcium from foods also had more estrogen in their bodies; the hormone is needed to maintain bone mineral density. Researchers can't yet explain the food-estrogen connection.

The research is preliminary and offers "a springboard to do something more, a hypothesis to test," said Armamento-Villareal, a bone specialist and assistant professor in the School of Medicine's division of bone and mineral diseases. It was published in the May issue of the American Journal of Clinical Nutrition.

Researchers asked 183 postmenopausal women to meticulously document their diet and their calcium supplement intake for seven days. They tested their bone mineral density and their urine for levels of estrogen.

The women then were divided into three groups: those who got at least 70 percent of their daily calcium from supplements, those who got the same amount from dairy products and other food, and those whose calcium-source percentages fell somewhere in between.

The "diet group" took in the least calcium, an average of 830 milligrams per day. Yet, the group had higher bone density in their spines and hip bones than women in the "supplement group," who consumed 1,030 milligrams per day.

Women in the "diet plus supplement group" tended to have the highest bone mineral density as well as the highest calcium intake at 1,620 milligrams per day.

An analysis showed that women in the "diet group" and the "diet plus supplement group" had higher levels of estrogen, needed for bone mineral density.

Dr. Robert Recker, who heads osteoporosis research at the Creighton University School of Medicine in Omaha, noted weaknesses in the study, which he said "is certainly not definitive."

Those who got calcium from their diet might have also taken in more vitamin D from milk, which would aid in calcium absorption. As for the estrogen connection, they might have eaten plant sources containing more of the hormone, he said.

"Nevertheless it's not to be ignored," Recker said. "Observation studies are very good for generating a hypothesis to be tested later in an outright experiment."

Dairy foods and calcium-fortified orange juice are excellent sources of calcium. Dark green, leafy vegetables also contain it, though it is not as readily absorbed as calcium from dairy, researchers said.

Armamento said she'd like to do a long-term study of teenagers whose bones are still developing to see what, if any, differences might emerge among young women taking calcium from diet versus supplements.

"It's a lifestyle issue," she said, noting that some teenagers avoid dairy products.

What is Vitamin D?

Vitamin D helps your body to absorb calcium. There are only a few food sources of vitamin D. Good sources of vitamin D are fortified foods and beverages like milk, soy drinks, and margarine (check the labels on these foods). Fish, liver, and egg yolk are the only foods that naturally contain vitamin D. If you do not eat vitamin D rich foods often, you may want to consider taking a vitamin D supplement. Most multiple vitamin supplements contain vitamin D.

Food Sources of Vitamin D1

Food

Serving

Vitamin D

Milk	1 cup	100 IU
Fortified rice or soy beverage	1 cup	100 IU
Fortified margarine	2 tsp	53 IU
Salmon, canned, pink	3 oz	530 IU
Tuna, canned, light	3 oz	200 IU

Recommended Vitamin D Intake1, 2, 4

Age (Male and Female)

0-1 year	400 IU/day1
1-50 years	200 IU/day 2, 3
51-70 years	400 IU/day
over 70 years	600 IU/day
1 2004 Health Canada recommendation.
2 Dietary Reference Intakes for Calcium, Phosphorus, Magnesium, Vitamin D, and Fluoride, 1997.
3 Women who are pregnant or breastfeeding do not need additional vitamin D.
4 People with osteoporosis may need more vitamin D. Check with your doctor or dietitian.

Chocolate improves blood vessel function: study

By Bill BerkrotSat Mar 24, 5:59 PM ET

Chocoholics were given further reason to rejoice on Saturday when a small clinical study showed that dark chocolate improves the function of blood vessels.

While the researchers cautioned against bingeing on bon bons, they said the findings of the trial were clear and called for larger such studies to confirm the results.

"In this sample of healthy adults, dark chocolate ingestion over a short period of time was shown to significantly improve (blood vessel) function," said Dr. Valentine Yanchou Njike of Yale Prevention Research Center, a co-investigator of the study.

The results, presented at the annual American College of Cardiology scientific meeting in New Orleans, add to mounting evidence of the health benefits of dark chocolate.

During the six-week trial, 45 people were given 8 ounces (227 grams) of cocoa without sugar, cocoa with sugar or a placebo each day.

An upper arm artery's ability to relax and expand to accommodate increased blood flow -- known as flow mediated dilation (FMD) -- was measured using high-frequency ultrasound before and after daily cocoa or placebo consumption.

Of the 39 subjects who completed the trial, FMD improved significantly in both cocoa groups -- by 2.4 percent among those who had it without sugar and 1.5 percent among those who had it with sugar. It dropped 0.8 percent in the placebo group.

"While the findings from this study do not suggest that people should start eating more chocolate as part of their daily routine, it does suggest that we pay more attention to how dark chocolate and other flavonoid-rich foods might offer cardiovascular benefits," Njike said.

Dietary Supplementation With Nitrate May Reduce Blood Pressure

Swedish researchers believe that they have demonstrated the blood pressure-lowering effect of orally ingested inorganic nitrate similar to that contained in many vegetables, supporting the beneficial cardiovascular effects associated with a diet rich in fruit and vegetables. In a small, short-term study, they showed that short-term dietary supplementation with inorganic nitrate reduced diastolic blood pressure (DBP) in young, normotensive adults. A report of the study, led by Prof. Eddie Weitzberg, MD, PhD (Karolinska Institute, Stockholm), and supported by the Swedish Research Council, the Swedish Heart and Lung Foundation, and the European Commission, has been published in The New England Journal of Medicine.[13] The study was based on the theory that inorganic nitrate is converted by symbiotic bacteria in the oral cavity into nitrite, NO, and secondary reaction products with vasodilating and tissue-protective properties.[14]

Prof. Weitzberg and his colleagues examined the effect of 3-day dietary supplementation with either sodium nitrate 0.1 mmol/kg of body weight per day or sodium chloride 0.1 mmol/kg per day (placebo) on blood pressure in 17 physically active, healthy volunteers (15 men and 2 women; mean age, 24 years; all nonsmokers). Subjects were randomized in a double-blind, crossover fashion for 2 different treatment periods during which the subjects received either nitrate or placebo, separated by a washout period of at least 10 days. During treatment, all subjects avoided foods with a moderate-to-high nitrate content. After nitrate supplementation, DBP and mean arterial pressure were significantly lower compared with placebo by an average of 3.7 mm Hg (P < .002) and 3.2 mm Hg (P < .003), respectively. Plasma nitrate and nitrite levels were significantly higher after nitrate ingestion than after placebo ingestion.

Prof. Weitzberg and his colleagues pointed out that the daily nitrate dose used in their study was equivalent to the amount normally found in 150-250 g of a nitrate-rich vegetable, such as spinach, beetroot, or lettuce. They noted that the Dietary Approaches to Stop Hypertension (DASH) diet, which recommends eating 4-5 servings of vegetables daily, has been shown in clinical trials to reduce blood pressure,[15-18] although no individual nutrient has been identified as responsible for this effect. The researchers noted that the blood pressure effect achieved with nitrate supplementation in their study was similar to that seen in the control group in the DASH study.[15] They do not know the mechanism by which nitrate may lower blood pressure and/or whether the effect can be maintained over the long term. These need to be clarified in future studies, they say, and they plan to do these in Sweden.