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Healthnotes Newswire (July 24, 2008)—Potatoes, often thought of as just a starch, are actually an important source of potassium; provide modest amounts of calcium, magnesium, phosphorus, and sulfur; and have small amounts of zinc, boron, copper, manganese, and iron. Cooking them reduces their mineral content, however, and a new study found that many of potatoes’ nutritious minerals are lost when they are cut into small pieces and then boiled. More nutritional value can be preserved by cooking them whole.

Heat depletes

In the study, published in the Journal of Food Science, six varieties of potato were washed and peeled, then cut into small cubes or shredded into strips. The potato cubes and strips were either placed in cold water overnight or boiled for ten minutes. Soaking resulted in minimal potassium loss, but boiling the potato cubes cut their potassium content by about 50%. Boiling shredded potatoes cost even more potassium—about 75% was lost. When potatoes in either form were soaked and boiled, the results were the same as when they were only boiled.

Other minerals showed similar trends: about 50% of the shredded potatoes and about 30% of the cubed potatoes lost their original sulfur, magnesium, zinc, and manganese during boiling. The amounts of phosphorus and iron were also significantly lower after boiling. Calcium, copper, and boron content were not consistently affected.

This degree of potassium loss was more dramatic than that seen in previous studies using whole peeled potatoes. Other research has shown that zinc and iron are preserved when the potato is boiled whole with its skin intact.

Why potassium matters

Potassium is necessary for maintaining normal fluid balance, acidity, and heart rhythm, and a healthy body keeps potassium carefully balanced with sodium. Although potassium is abundant in fruits and vegetables, many people don’t get enough from their diets, especially relative to sodium, an imbalance that is linked to high blood pressure.

For people with kidney disease, too much potassium can be more of a concern than too little. Soaking potatoes in cold water before cooking them, known as leaching, is a common practice among people with kidney disease on potassium-restricted diets, but this study’s results suggest that leaching is unnecessary. Simply cutting the potatoes into small pieces and boiling them has the same potassium-depleting effect.

Most of us, however, can and should eat lots of potassium-rich foods, including tomatoes, sweet potatoes, winter squash, avocadoes, oranges, bananas, and, of course, potatoes. “Although cutting potatoes into small pieces is appealing because it reduces cooking time, it is appears that this is not the most nutritious way to prepare them,” said study co-author Dr. Shelley Jansky of the US Department of Agriculture. “People who want to get the most out of their potatoes should boil them whole and unpeeled, or consider other cooking methods like baking or roasting.”

(J Food Sci 2008;75:H80–5)

Healthnotes Newswire (June 26, 2008)—As most people know, a recent salmonella food poisoning scare was traced to raw tomatoes, leading to national attention on tomato sources and causing many people and food purveyors to temporarily abandon all fresh tomato products. Fortunately, the scope of the outbreak has been identified, and now tomatoes from regions other than some parts of Florida and Mexico have been ruled safe, as have cherry tomatoes, grape tomatoes, tomatoes still attached to the vine from any area, and processed tomato products.

Attack of the tomatoes

The US Food and Drug Administration tracked the source of the 550-plus cases of food poisoning that have been reported since April to contaminated raw red plum, red Roma, round red tomatoes, and certain products containing these tomatoes. Though the FDA has narrowed the source of the outbreak to locations in Florida or Mexico, they are not certain of the exact source and point out that tomatoes grown in some regions in Florida and Mexico are also safe to eat.

It should give consumers confidence that all types of tomatoes grown in most states have not been associated with the outbreak (for the FDA’s list, visit www.fda.gov/oc/opacom/hottopics/tomatoes.html). If you are not sure about the source of your tomatoes or fresh tomato products such as salsa, check with the retailer or product manufacturer. The FDA warns that tomatoes from unknown sources should not be eaten.

What you should know about salmonella

Salmonella can thrive in raw food that is not kept to minimum cold storage and cooking temperatures (see FDA’s recommendations at www.fsis.usda.gov/FactSheets/Salmonella_Questions_&_Answers). Cooking to proper heat (145°F) will kill most salmonella, so concerns are primarily about raw or undercooked foods. Small amounts of bacteria are known to cause many cases of salmonella poisoning, most of which go unreported because the cases are mild and resolve without medical intervention.

A person can develop salmonella food poisoning from eating or drinking something contaminated with the bacteria or being in close contact with a contaminated human or animal. Salmonella may pass from an animal’s intestinal tract to its feces, ultimately ending up in soil where it may contaminate food. Infected humans may also spread salmonella to each other and contaminate food through improper hygiene. Raw meat, poultry, eggs, milk, and vegetables are food sources that have been known to become contaminated with salmonella.

Infection with salmonella may occur within hours or a couple of days after being exposed to the bacteria. Symptoms may include diarrhea, abdominal cramping, nausea, fever, muscle aches, headache, and others. If these symptoms develop, see a doctor. Most people improve without antibiotic treatment but if the condition spreads outside of the intestinal tract and becomes systemic they may need antibiotic treatment.

To help prevent the salmonella poisoning, remember the following:

• Wash hands before and after preparing food, and before eating.

• If you suspect you are infected with salmonella, do not prepare and serve food.

• Fully cook meat, poultry, and eggs.

• Buy food, including milk and vegetables, from reputable and high-quality sources where safe food-handling and hygiene are practiced.

• If you hear about new outbreaks, check with sources such as the FDA so you can make health decisions based on the best available information rather than hearsay.

“Tomatoes are an important part of the diet and are rich in antioxidants such as vitamins A and C, and lycopene, which have been linked to cancer prevention and other important health effects,” James Gerber, MS, DC, who teaches nutrition in several institutions of higher learning. So, take this opportunity to check your family’s food-handling practices and follow the FDA’s recommendations, but don’t stop eating tomatoes.

(Salmonellosis Outbreak in Certain Types of Tomatoes US Food and Drug Administration www.fda.gov/oc/opacom/hottopics/tomatoes.html)

Healthnotes Newswire (June 19, 2008)—Until recently, attention deficit–hyperactivity disorder (ADHD) was considered mainly a childhood disorder. Today it is recognized as a common condition in many adults throughout the world, and now there is evidence that the condition may interfere with work performance).

The World Health Organization dustributed a World Mental Health Survey Initiative in ten countries to collect data from more than 11,000 people, ages 18 to 44. Approximately 3.5% of workers had adult ADHD, and men were more likely than women to suffer from the disorder. When compared with their colleagues, people with ADHD were less productive. This lost time was due to poor work quality, reduced quantity, or a complete inability to carry out their tasks. The survey revealed that most adults are not treated for their ADHD.

Symptoms of adult ADHD may include difficulty with concentrating or focusing on a task, being easily distracted, difficulty with following instructions, problems with organizing and prioritizing, and restlessness. The disorder may affect a person’s work performance because he or she is not able to complete a task on time or at all due to lack of focus or procrastination, or because the person is often very busy but not accomplishing a lot. People with ADHD often have other mental or substance abuse disorders that may affect their work performance as well.

“ADHD is a relatively common condition among working people in the countries studied and is associated with high work impairment in these countries,” according to the study authors. “This impairment, in conjunction with the low treatment rate and the availability of cost-effective therapies, suggests that ADHD would be a good candidate for targeted workplace screening and treatment programs.”

Finding focus

Treatments for the condition include self-regulating techniques such as learning about the disorder, instituting time and project management techniques, and creating structure that can be followed. Some people seek professional help for therapy to help them regulate their behaviors, and medications are available to help ease symptoms.

Natural treatments that have been found to benefit children with ADHD include consuming less refined sugar and food additives, identifying and avoiding allergenic foods, and supplementing with B vitamins, magnesium, and essential fatty acids. These treatments have not been studied in adults with ADHD.

(Occup Environ Med 2008; doi:10.1136/oem.2007.038448)

Healthnotes Newswire (June 19, 2008)—Older women with low back pain might benefit by getting some extra vitamin D, reports a study in the Journal of the American Geriatrics Society. Low levels of vitamin D can lead to weakened bones, lowered immune function, and sometimes pain.

The new study included 958 people over age 65 who gave information about the location of their pain, from their midback to their feet. Blood samples were taken to measure vitamin D levels.

Women were more likely than men to have moderate or severe pain in some part of their bodies, and women who were vitamin D deficient were almost twice as likely to suffer from low back pain as were people with normal vitamin D levels. Vitamin D status didn’t seem to affect low back pain in men, nor did it influence pain in other parts of the bodies of men or women.

How (and how much) do you D?

The “sunshine vitamin” is produced in the body after exposure of the skin to sunlight. Exposing the face, arms, and hands to sunlight for 15 minutes three times per week year-round can help boost vitamin D levels. Vitamin D also occurs naturally in a few foods like egg yolks and fatty fish such as salmon and mackerel. Dairy products, juices, and cereal products are often fortified with vitamin D.

Just how much vitamin D is best for optimal health is a hot topic. A growing body of evidence suggests that 400 IU per day, the amount found in many multivitamin products, is not enough to maintain optimal levels. Many people appear to need 1,000 IU per day and in some cases even more. The body’s ability to synthesize vitamin D diminishes with age, putting older people at increased risk for deficiency.

The Institute of Medicine has concluded that long-term intake of 2,000 IU per day is safe for most people. Some doctors recommend even more, such as 2,000 to 4,000 IU per day depending on the season, but people taking those amounts should be monitored by a doctor.

Along with the many other benefits adequate D offers the body, such as supporting calcium absorption that keeps bones strong, the authors of the new study conclude that the new study’s “findings suggest it may be worthwhile to question older adults about their pain and screen older women with significant back pain for vitamin D deficiency.”

(J Am Geriatr Soc 2008;56:785–91)

Healthnotes Newswire (May 8, 2008)—Omega-3 fatty acids from fish offer many benefits to developing babies during pregnancy. But do contaminants such as mercury make eating fish unsafe? According to a new study in the American Journal of Epidemiology, pregnant women who eat two or more servings of fish each week may be providing their children with important nutrients that aid in cognitive development. Choosing fish with low mercury content appears to be even more beneficial.

Fish contains important nutrients such as omega-3 fatty acids and is generally high in protein and low in saturated fat. Many studies have suggested that eating fish several times per week is good for heart health and for preventing diseases such as a cancer. But fish may also contain contaminants such as unhealthy mercury. As a result, the Environmental Protection Agency (EPA) recommends that pregnant women not eat more than two 6-ounce servings of fish per week.

The authors of this new study were concerned that if pregnant women limit fish intake, their babies may not receive enough omega-3 fatty acids, which could impair the brain’s cognitive development. To determine the risks and benefits of eating fish during pregnancy on child development, the authors looked at dietary habits of 341 pregnant women, their mercury levels during pregnancy, and the cognitive development of their children at age three.

Women who ate the most fish (more than two servings per week) had higher mercury levels. However, higher fish intake was associated with better cognitive test performance, regardless of mercury levels. Compared with the children of women who never ate fish, the children of women who ate more than two servings of fish per week but had the lowest mercury levels had better cognitive test performance.

“Recommendations for fish consumption during pregnancy should take into account the nutritional benefits of fish as well as the potential harms from mercury exposure,” said Emily Oken, MD, and her colleagues from Harvard Medical School and Harvard School of Public Health. The authors believe that if mercury contamination were not present, the cognitive benefits of eating fish would be greater. They point out that other contaminants such as polychlorinated biphenyls may also be present in fish and were not measured in this study but may have an adverse effect on child development.

Best bets for eating fish during pregnancy

For women who are or may become pregnant, choose fish that are likely to have lower mercury levels such as:

• Canned light tuna

• Shrimp

• Salmon

• Pollock

• Catfish

The EPA points out that fish that is used for fish sticks or fast food sandwiches tend to be fish that are lower in mercury content. Fish best avoided by pregnant women include shark, swordfish, king mackerel, and tilefish.

(Am J Epidemiol 2008 Mar 28)

(What You Need to Know About Mercury in Fish and Shellfish. Environmental Protection Agency. www.epa.gov/waterscience/fish/advice/)

Healthnotes Newswire (May 8, 2008)—Calcium helps build stronger bones in young girls—but they need to get enough of it without interruption, reports a study in the American Journal of Clinical Nutrition.

A recent analysis of several studies concerning calcium intake and bone health in young girls questioned the value of calcium supplementation for increasing bone density. The new study incorporated additional measures of bone turnover as well as bone accumulation in the body to see the effects of calcium supplementation in preteen girls. (It’s thought that bone accumulation more accurately predicts bone health later in life than looking at bone density alone.)

In the new study, 96 girls (average age 12 years) getting low amounts of calcium (about 636 mg per day on average) were given a supplement providing 792 mg of calcium per day or a placebo for 18 months. During the supplementation period and for two years afterward, they were tested on measures of bone density, bone mineral content, and the rate of bone turnover in the body.

Girls who took the calcium supplement had significantly greater bone density, higher rates of bone accumulation, and less bone turnover than girls in the placebo group during the supplementation period. Two years after the supplements had been discontinued, however, the positive effects were no longer seen. “Calcium supplementation enhances bone mineral accrual in teenage girls, but the effect is short-lived,” the authors said.

An Adequate Intake (AI) level for calcium of 1,300 mg per day has been set for children ages 9 to 13. The Continuing Survey of Food Intakes of Individuals found that 87% of girls between ages 12 and 19 do not get the recommended intake for calcium and that teen girls get an average of only about 600 to 700 mg of calcium per day.

During childhood, the rate of bone accumulation is greater than the rate of bone loss. By middle age, bone loss about equals gain. In women, bone loss exceeds gains after menopause. So, it’s important to maximize bone accumulation during youth to help protect against osteoporosis later in life.

Tips to boost calcium intake

• Include low-fat dairy products such as milk, cheese, and yogurt in the diet.

• Choose calcium-rich vegetables like broccoli, Chinese cabbage, kale, and turnip greens.

• Coffee, tea, and sodas can lead to calcium loss; opt for water or calcium-fortified fruit juices instead.

• Vitamin D enhances calcium absorption, so make sure to get some of the sunshine vitamin and look for vitamin D–fortified foods.

• Too much sodium can cause the body to dump precious calcium; try lemon juice in place of salt in dips and spreads or squeezed over steamed veggies.

• Choose vegetable protein, as excess protein in meat products can lead to calcium loss. Select tofu that’s packed in a calcium solution for a boost of this essential mineral.

(Am J Clin Nutr 2008;87:455–62)

Healthnotes Newswire (July 26, 2007)—According to a new meta-analysis, conjugated linoleic acid (CLA) may cause modest, short-term loss of body fat in certain people, but unanswered questions about the safety of long-term use indicate that it’s premature to embrace it as the new go-to supplement for weight loss. 

CLA is a fatty acid that has been shown to reduce body fat in animals, although its effect on human body fat has been unclear. The meta-analysis, published in the American Journal of Clinical Nutrition, reviewed 18 studies, in order to determine whether supplementing with CLA reduces human body fat.

Results showed that people supplementing with an average of 3.2 grams per day of CLA lost a modest but significant amount of body fat: about 0.2 pounds per week compared with those people who took placebo (olive or safflower oil in most studies).

But the meta-analysis had its limitations: studies reviewed were of short duration (making the long-term effects of CLA unclear), and included other interventions, such as diet and exercise, that potentially contributed to weight loss, thereby calling the study results into question. The authors also state that it is unclear how much CLA a person has to take during what length of time to achieve optimal body fat loss. They concluded that it is not possible to draw conclusions about the effects of CLA on long-term weight maintenance.

CLA has several different chemical structures (called isomers), and certain isomers may be more effective in reducing body fat in humans than other isomers, as has proven true in animal studies, but further research is needed. The authors report that CLA was not associated with severe adverse effects in the studies they reviewed but there have been reports of CLA adversely affecting several risk factors for chronic disease.

“In clinical trials, supplementation with CLA has produced various unwanted effects, including increases in serum cholesterol levels, insulin resistance, and markers of inflammation. Additional research is needed regarding long-term safety of CLA before its routine use can be recommended,” said Healthnotes Chief Science Editor Alan Gaby, MD, an expert in medical nutrition.

People who are overweight or obese often turn to supplements such as CLA in hopes of losing weight or maintaining a healthy weight after weight loss. Healthcare professionals advise that it is important to understand the risks and benefits of dietary supplements and often recommend instead that people looking for safe, long-term weight loss focus primarily on modifying lifestyle behaviors such as diet and exercise.

(Am J Clin Nutr 2007;85:1203–11)

Healthnotes Newswire (January 10, 2008)—The next time you enjoy a cup of tea, don’t forget the lemon. A study in Molecular Nutrition and Food Research found that adding citrus juice helps preserve the natural antioxidants in green tea called catechins, making it a winning beverage for better health.

Drunk throughout Asia for centuries, green tea is produced by heating, rolling, and drying the fresh leaves of the Camellia sinensis plant. Unlike black tea, which is produced from the same plant, green tea is not fermented; skipping the fermentation step helps preserve the tea’s catechin content.

Catechins are believed to play a role in the prevention of chronic diseases like cancer (including colon, breast, and prostate cancers) and heart disease. The only catch is that when these disease-fighting substances are drunk as a tea, they might not survive the digestive process.

The new study looked at the effect of how you take your tea—with different preservatives such as ascorbic acid (vitamin C) or with various creamers or juices—on the levels of catechins available for absorption. “Teas and tea mixes could be of great value in reducing disease severity and risk if factors associated with its protective activity are identified,” the authors noted.

Citrus juices significantly increased catechin levels following laboratory-simulated digestion, as did ascorbic acid, soymilk, rice milk, and cow’s milk. “Beverages prepared with ascorbic acid contents as low as 50% of the RDI [recommended daily intake] would likely provide effective protection,” the team commented. This amount is found in many ready-to-drink tea preparations.

Adding different creamers to green tea increased the available catechin levels from less than 20% to as much as 69%. Citrus juices were the clear winner, though, resulting in the maximum catechin recovery of any preparation. The highest catechin levels were found by adding lemon juice, followed by orange, lime, and grapefruit juice.

While different tea preparations still need to be studied under true digestive conditions, adding some lemon to your tea could be a tasty way to boost the benefits of this ancient infusion. Keep a fresh lemon or a bottle of preservative-free natural lemon juice in the refrigerator as a handy accompaniment to your green tea.

(Mol Nutr Food Res 2007;51:1152–62)

Healthnotes Newswire (December 20, 2007)— Does Vitamin C Cure the Common Cold? By Jane Hart, MD 

At the first sign of a cold, many people reach for the vitamin C in hopes of warding off the illness or easing symptoms. A new study looking at the effects of vitamin C on the development, duration, and severity of a cold, suggests that while vitamin C may not reduce the incidence of colds in a general population, taking vitamin C may, in fact, reduce the duration of a cold and help prevent a cold in certain people.

Does vitamin C shorten a cold?

If you take it before the cold starts. The authors of the study reviewed 30 research trials that included 11,350 people who took 200 mg or more of vitamin C daily at various stages of a cold. Results of the review showed that taking vitamin C before a cold starts may reduce the duration by 8% for adults and 13.6% for children.

Does it reduce risk?

Only at “extremes.” The review also found that vitamin C taken before a cold starts does not reduce the incidence of colds in a general adult population but may reduce the incidence in people exposed to extreme physical or cold (temperature) stress. For example, a group of athletes and soldiers on sub-Arctic exercises who took daily vitamin C reduced cold risk by 50%.

Does it make a cold less severe?

Not if you’re already sick. According to the reviewed trials, vitamin C’s effects on cold severity were inconsistent. A slight benefit was attributed to vitamin C in reducing days absent from school or work, but according to the review no significant effect has been seen in trials to date on the duration or severity of colds when vitamin C is started after symptoms begin.

What do the experts say?

Critics of the current review suggest that 1 to 3 grams of vitamin C is too small an amount and that research is needed on the effects of higher doses. Dr. Harri Hemila, lead author of the study, and his colleague state that, “studies on the therapeutic use of high doses of 4 grams and 8 grams on the day of the onset of respiratory symptoms are tantalizing and deserve further assessment.” Dr. Harri Hemila and his colleague state that “there seems no justification for routine megadose vitamin C supplementation in the normal population.” They add that taking vitamin C preventatively “may be justified in those exposed to severe physical exercise or cold stress or both.”

They also point out that to date none of the trials that looked at using vitamin C after a cold begins have examined the effect of vitamin C on children, even though trials that used vitamin C preventatively have found a substantially greater beneficial effect on duration in children, and they recommend further research in this area.

What’s the bottom line?

While vitamin C has been shown to affect disease resistance in numerous animal studies, we still do not have the full answer on how much vitamin C might help people ward off disease. And since the review looked at 30 studies that used different amounts for different lengths of time, the optimal amount for combating the cold remains to be discovered. For now, a person suffering from cold symptoms should eat a balanced diet that provides a wide variety of vitamins and minerals needed for health, and talk to a doctor about an appropriate amount of supplemental vitamin C to help shorten the duration.

Alan R. Gaby, MD, Healthnotes chief science officer, has concluded from his review of the vitamin C research, that adults who take 500 to 1,000 mg of vitamin per day preventively, and increase to 1,500 to 4,000 mg per day at the first sign of a cold, can reduce the duration and severity of colds by approximately 30%.

(Cochrane Database of Systematic Reviews 2007:3; article number CD000980. doi:10.1002/14651858.cd000980.pub3.)