Monday, March 20, 2023
Editor's Note:
Nutrition plays a vital role in health promotion and disease prevention, but studies on the potential benefits and risks associated with diet and supplementation are many and varied.
In this slideshow that focuses on women's health, Dr. Sandra A. Fryhofer summarizes some of the key research published during the past year that investigated the effects of a particular nutrient or dietary supplement on the risk for chronic diseases, such as cancer and stroke. Studies that looked at the prevention or treatment of conditions, such as macular degeneration and menopausal vasomotor symptoms, are also presented.
Protecting Cardiovascular Health With Fish
Young women who eat fish high in omega-3 fatty acids can cut their risk for heart disease. In a study from Denmark, those who didn't eat fish had triple the risk for heart disease when compared with women who ate fish every week.[1]
Older women can cut their risk of heart failure by eating dark fish. In the study, a follow-up to the Women's Health Initiative, those who ate 5 or more weekly servings of broiled or baked fish had a 30% lower risk for heart failure compared with women who ate less than 1 serving a month. Fried fish was linked to increased heart failure risk.[2]
Pregnant women can also benefit; moderate fish intake (3 servings/week) during gestation may cut the risk for repeat preterm birth.[3]
Antioxidant Effects of Coffee
In a study of coffee consumption and risk for stroke in women, women who drank 1-5 cups of coffee a day cut their risk for stroke by 25%.[4] Coffee contains phenolic compounds with antioxidant effects that improve endothelial function, increase insulin sensitivity, and reduce inflammation.
Lower Risk for Endometrial Cancer
Drinking 4 or more cups of coffee a day may lower the risk for endometrial cancer by 25% as compared with drinking less than 1 cup a day. In this study, drinking other caffeinated beverages, such as tea, didn't have the same beneficial effects. The strongest protective effects were seen in obese coffee drinkers.[5]
More on Coffee: A Few Cups a Day Keep Depression at Bay?
This is the first longitudinal study looking at how coffee affects the mental health of women.
Women who drank more caffeinated coffee experienced less depression, and the more coffee, the better the effects. Compared with women who drank little or no coffee, women who drank 2-3 cups a day had a 15% decreased risk for depression. Results were even better for women who drank more coffee. Women who drank at least 4 cups a day had a 20% decreased risk for depression.
The positive results were seen only for caffeinated coffee intake. Neither decaf coffee, caffeinated tea, nor sugared soft drinks seemed to lower depression risk. Even chocolate didn't do it.[6]
Safflower Oil: Friendly for Women With Diabetes
A small, randomized, double-masked, crossover study of 55 postmenopausal obese women with diabetes found that a daily dose of safflower oil (1 2/3 teaspoons) improves blood sugar and lipids and decreases inflammation.[7] Positive results were seen in just 16 weeks.
Safflower oil is rich in omega-6 polyunsaturated fatty acids (PUFAs). The American Heart Association recommends that 5%-10% of calories come from omega-6.[8] Total recommended intake can vary from 12 to 22 g per day, depending on age, gender, and activity level. Omega-6 intake helps lower blood pressure. Replacing saturated fats with PUFAs lowers risk for heart disease.
Safflower oil can be used in cooking, baking, and dressing for salads.
Verdict on Vitamins: Less Is More?
For vitamin and mineral supplements, more is not necessarily better and could be harmful. Data from the Iowa Women's Health Study analyzed self-reported supplement use in more than 38,000 women 55-65 years of age. Instead of promoting health, dietary supplements, including multivitamins, vitamin B6, folic acid, magnesium, and copper, were linked to increased risk for death. Supplemental iron was most concerning: The increased mortality risk was dose dependent.[9]
The study looked only at older women and did not explore possible mechanisms. It does not apply to childbearing women, who should continue to take multivitamins containing 400 µg of folic acid to prevent neural tube defects. The research serves as a reminder that supplements can't replace a healthy diet.
Flaxseed for Treating Hot Flashes: A Feat or a Flop?
Some women take phytoestrogens as a natural remedy for menopausal symptoms. Flaxseed is a good dietary source of fiber, omega-3 fatty acids, and lignans, a phytoestrogen. It makes sense, then, that flaxseed could be helpful. But theory is not always reality.
In a small, randomized, placebo-controlled, 28-week trial at the Mayo Clinic in Rochester, Minnesota, 188 women were randomly assigned to receive either a flaxseed bar or a fiber bar. For hot flash relief, the findings for flaxseed were a flop. No significant improvement in symptoms was observed.[10]
For some researchers, this comes as no surprise. A 2007 pilot study showing 57% improvement in intensity of hot flashes had no placebo control group.[11] Flaxseed side effects include nausea, bloating, and diarrhea.
Dietary Strategies to Prevent Allergies in Babies
High intake of margarine, vegetable oils, citrus fruits, raw sweet peppers, and celery during pregnancy was linked to an increased risk for eczema and allergen sensitivity in the baby. However, babies born to women who ate lots of fish while pregnant were less likely to have asthma.[12]
Some things never change: Breast milk is best. To prevent allergies, timing of solid food introduction matters -- not too early and not too late. Begin solid foods no earlier than 4 months and no later than 6 months of age. Delaying solid food introduction to 4 months of age was linked to a decreased risk for eczema.[12]
These findings are supported by guidelines from the American Academy of Pediatrics.[13]
Benefits of Diet on Macular Degeneration Risk
Age-related macular degeneration (AMD) is a leading cause of irreversible vision loss in adults. Recent studies conducted in women suggest dietary changes that can help stave off this disease.
Regular consumption of fish and omega-3 fatty acids is linked to reduced risk for macular degeneration.[14] It may also reduce disease progression and development of advanced AMD. Randomized trials are needed to confirm this protective effect.
Beating the Odds With Vitamin D
High vitamin D levels are linked to decreased risk for early AMD changes in women younger than 75 years of age. Increase intake of vitamin D from both foods and supplements.[15]
Glycemic Impact of Nuts
A small study of 20 patients with metabolic syndrome suggests that adding a few handfuls of pistachios to a high-glycemic meal can lower postprandial glucose and insulin levels. This study builds on previous research that suggests that combining pistachios with carbs may blunt postprandial glycemic response. This study, presented at the International Diabetes Federation World Diabetes Congress 2011, was funded by the Western Pistachio Association.[16]
A previous study in the Archives of Internal Medicine found that daily consumption of 2.4 oz of nuts – any type of nuts – improved lipids.[17] Nuts are dense in calories, so a couple of handfuls are probably too much. But a small handful of nuts a day, including pistachios, is probably a good idea.
Dietary Antioxidants and Stroke Risk
After heart disease, stroke is the leading killer throughout the world. That's why preventing stroke is so important. A new study finds that a diet high in antioxidants may do just that.
High antioxidant consumption through fruits, vegetables, whole grains, tea, and even chocolate was linked to 17% lower stroke risk in healthy women. For women with a history of heart disease, the stroke-preventing benefit of antioxidants was even better: Hemorrhagic stroke risk was cut by 45%. That's nearly half the risk![18]
This study looked at antioxidants in foods, not supplements. Earlier studies failed to show this benefit with supplements. But even so, an antioxidant-rich diet did seem to make a difference.
More Good News About Folic Acid
All women of childbearing potential need 400 µg daily of folic acid, which cuts the risk for neural tube defects by as much as 78%. The neural tube is formed before most women know they are pregnant. Enriched grains and many other foods are fortified with folic acid, but it's easier to take a multivitamin.
Even more good reason for folic acid supplementation: A new study finds that babies of moms who took folic acid during the first 1-2 months after conception were much less likely to have language delays.[19]
Another new study dispels the myth that taking folic acid might increase the risk for asthma in the baby. Researchers found no increased risk for asthma, wheezing, atopy, or decreased lung function in babies of moms who took folic acid during pregnancy.[20]
The More Colorful the Diet, the Better
In Case You Missed It...
A study has linked high intake of anthocyanins, the blue and red pigments in colorful fruits and vegetables – blueberries, strawberries, blackcurrants, blood oranges, raspberries, eggplant – to a lower risk of developing high blood pressure. People who ate the most blueberries and strawberries had a 10% reduction in blood pressure.[21] Anthocyanins are flavonoids that target and regulate endothelial nitric oxide production, thus relaxing the vessel wall.
Starting Early and Eating Often
The most benefit, a 12% drop in blood pressure, was seen in individuals younger than 60 years of age, in the highest quintile of anthocyanin consumption. An average serving of blue- or red-pigmented fruit contains over 500 mg of anthocyanins.
Slideshow Author
Sandra Adamson Fryhofer, MD
Clinical Associate Professor of Medicine, Emory University School of Medicine, Atlanta, Georgia; Past President, American College of Physicians, Philadelphia, Pennsylvania
Disclosure:
Sandra Adamson Fryhofer, MD, has disclosed the following relevant financial relationships:
Served as a director, officer, partner, employee, advisor, consultant or trustee for: American College of Physicians (past president and former member of the Board of Regents); AMA Council on Science & Public Health (Member and Chair-Elect); AMA Commission to End Health Care Disparities; AMA representative to National Priorities Partnership; American Medical Association (member ACP delegation); ACP Adult Immunization Advisory Board (member); Alternate ACP Liaison to ACIP (serve on working groups); ACP Performance Measurement Committee (member); ACP (representative and member); American Academy of Pediatrics (committee member – Cocooning Strategy to Prevent Pertussis Initiative)
Received conference tuition waiver: National Immunization Conference (member of external planning committee)
Served as a speaker or member of a speaker's bureau for: US Food & Drug Administration (expert testimony on REMS); US Health Subcommittee, House Energy and Commerce Committee (expert testimony on antibiotics)
Received income an amount equal to or greater than $250 from: WebMD Health (Medscape - paid contributor); Stericycle (educational video host); ACP Adult Immunization Guide (paid author); CDC/Joint Commission Influenza Project Technical Advisory Panel (honorarium); Women's Day Magazine (Health & Fitness Advisory Board & weekly health blog contributor)
Owns: Private Internal Medicine Practice
