Archives for July 2011

Potassium Rich Foods

Food Sources of Potassium ranked by milligrams of potassium per standard amount, also showing calories in the standard amount. (The AI for adults is 4,700 mg/day potassium.)

Food, Standard Amount

Potassium (mg)

Calories

Sweetpotato, baked, 1 potato (146 g)

694

131

Tomato paste, ¼ cup

664

54

Beet greens, cooked, ½ cup

655

19

Potato, baked, flesh, 1 potato (156 g)

610

145

White beans, canned, ½ cup

595

153

Yogurt, plain, non-fat, 8-oz container

579

127

Tomato puree, ½ cup

549

48

Clams, canned, 3 oz

534

126

Yogurt, plain, low-fat, 8-oz container

531

143

Prune juice, ¾ cup

530

136

Carrot juice, ¾ cup

517

71

Blackstrap molasses, 1 Tbsp

498

47

Halibut, cooked, 3 oz

490

119

Soybeans, green, cooked, ½ cup

485

127

Tuna, yellowfin, cooked, 3 oz

484

118

Lima beans, cooked, ½ cup

484

104

Winter squash, cooked, ½ cup

448

40

Soybeans, mature, cooked, ½ cup

443

149

Rockfish, Pacific, cooked, 3 oz

442

103

Cod, Pacific, cooked, 3 oz

439

89

Bananas, 1 medium

422

105

Spinach, cooked, ½ cup

419

21

Tomato juice, ¾ cup

417

31

Tomato sauce, ½ cup

405

39

Peaches, dried, uncooked, ¼ cup

398

96

Prunes, stewed, ½ cup

398

133

Milk, non-fat, 1 cup

382

83

Pork chop, center loin, cooked, 3 oz

382

197

Apricots, dried, uncooked, ¼ cup

  378

78

Rainbow trout, farmed, cooked, 3 oz

375

144

Pork loin, center rib (roasts), lean, roasted, 3 oz

371

190

Buttermilk, cultured, low-fat, 1 cup

370

98

Cantaloupe, ¼ medium

368

47

1%-2% milk, 1 cup

366

102-122

Honeydew melon, 1/8 medium

365

58

Lentils, cooked, ½ cup

365

115

Plantains, cooked, ½ cup slices

358

90

Kidney beans, cooked, ½ cup

358

112

Orange juice, ¾ cup

355

85

Split peas, cooked, ½ cup

355

116

Yogurt, plain, whole milk, 8 oz container

352

138

Source: Nutrient values from Agricultural Research Service (ARS) Nutrient Database for Standard Reference, Release 17. Foods are from ARS single nutrient reports, sorted in descending order by nutrient content in terms of common household measures. Food items and weights in the single nutrient reports are adapted from those in 2002 revision of USDA Home and Garden Bulletin No. 72, Nutritive Value of Foods. Mixed dishes and multiple preparations of the same food item have been omitted from this table. 

Treating Obesity Via Brain Glucose Sensing

Photo: FREEIMAGES.co.uk

The past two decades have witnessed an epidemic spread of obesity-related diseases in Western countries. Elucidating the biological mechanism that links overnutrition to obesity could prove crucial in reducing obesity levels. In the July 26 issue of PLoS Biology, Dr. Dongsheng Cai and his research team at Albert Einstein College of Medicine describe a pathway that directs the brain to sense the body’s glucose dynamics, and they find that a defect of this glucose sensing process contributes to the development of obesity and related disease. Importantly, the team also found that correction of this defect can normalize the whole-body energy balance and treat obesity.

The hypothalamus in the brain plays a key role in controlling energy and body weight balance. To maintain balance between energy intake and energy expenditure, the hypothalamus constantly gauges the whole-body’s energy levels by sampling circulating hormones (e.g. insulin and leptin) as well as nutrients (e.g., glucose). Although we know quite a bit about the hormonal pathways in the hypothalamic regulation of feeding, the mechanisms for hypothalamic nutrient sensing are much less clear. Moreover, a causal link between a nutrient sensing defect and obesity remains to be established. The team led by Dr. Cai discovered a novel role of a protein complex, hypoxia-inducible factor (HIF), in hypothalamic glucose sensing and whole-body energy balance in mice.

HIF is a nuclear transcription factor which induces hypoxia response. When tissue oxygen level is low, HIF is activated to promote cellular metabolic adaption and survival. Recent research has appreciated the involvement of HIF in the metabolism of tumor cells. “However, an intriguing but unexplored question is whether HIF can be important for the regulation of whole-organism metabolism, and if so, which tissue and cells are responsible.” says Cai, who is an expert in neuroendocrinology and metabolism.

Cai and his group examined HIF in the hypothalamus and, surprisingly, found that it can be activated by glucose and that this regulation was associated with appetite control in mice. In identifying the cellular and molecular basis, the team found that in response to glucose, HIF acts in a unique group of hypothalamic nutrient-sensing neurons to induce expression of POMC gene – a gene which has been known to play a key part in hypothalamic control of feeding and body weight. Most excitingly, the team demonstrated the therapeutic potential of targeting hypothalamic HIF to control obesity. By enhancing the hypothalamic HIF activity via gene delivery, mice become resistant to obesity despite the condition of nutritional excess.

“It was an exciting discovery,” explains Cai, “Our study is the first to show that beyond its classical oxygen-sensing function in many cells, HIF in the hypothalamic neurons can sense glucose to control the whole-body balance of energy intake and expenditure which is critical for body weight homeostasis.” Overall, this study reveals a crucial role for neuronal HIF in bridging the brain’s glucose sensing with the brain’s regulation of body weight and metabolic physiology. These findings also highlight a potential implication for developing neuronal HIF activators in treating and preventing obesity and related diseases.

 

Reference

Zhang H, Zhang G, Gonzalez FJ, Park S-m, Cai D.  Hypoxia-Inducible Factor Directs POMC Gene to Mediate Hypothalamic Glucose Sensing and Energy Balance Regulation. PLoS Biol 2011; 9 (7):  e1001112. doi:10.1371/journal.pbio.1001112

 

 

Omega-3s May Reduce Diabetes Risk: 3 Studies Compare Plant & Marine Sources

Increased blood levels of omega-3 fatty acids from plant or marine sources are associated with reduced risk of type-2 diabetes, according to three new studies in the American Journal of Clinical Nutrition.

 

 

J Clin Nutr August 1, 2011; 94 (2)

 

Editorial

Edith JM Feskens
The prevention of type 2 diabetes: should we recommend vegetable oils instead of fatty fish?
Am J Clin Nutr 2011 94: 369-370;
First published online July 6, 2011.
doi:10.3945/ajcn.111.020172
Full Text       Full Text (PDF)

 

Nutritional epidemiology and public health

Diana P Brostow, Andrew O Odegaard, Woon-Puay Koh, Sue Duval, Myron D Gross, Jian-Min Yuan, and Mark A Pereira
Omega-3 fatty acids and incident type 2 diabetes: the Singapore Chinese Health Study
Am J Clin Nutr 2011 94: 520-526;
First published online May 18, 2011.
doi:10.3945/ajcn.110.009357
Abstract       Full Text       Full Text (PDF)

 

Luc Djoussé, Mary L Biggs, Rozenn N Lemaitre, Irena B King, Xiaoling Song, Joachim H Ix, Kenneth J Mukamal, David S Siscovick, and Dariush Mozaffarian
Plasma omega-3 fatty acids and incident diabetes in older adults
Am J Clin Nutr 2011 94: 527-533;
First published online May 18, 2011.
doi:10.3945/ajcn.111.013334
Abstract       Full Text       Full Text (PDF)

 

Raquel Villegas, Yong-Bing Xiang, Tom Elasy, Hong-Lan Li, Gong Yang, Hui Cai, Fei Ye, Yu-Tang Gao, Yu Shyr, Wei Zheng, and Xiao-Ou Shu
Fish, shellfish, and long-chain n−3 fatty acid consumption and risk of incident type 2 diabetes in middle-aged Chinese men and women
Am J Clin Nutr 2011 94: 543-551;
First published online June 15, 2011.
doi:10.3945/ajcn.111.013193
Abstract       Full Text       Full Text (PDF)

  

 

How Maternal Smoking Or Nicotine Use Increases The Risk Of Cardiovascular Disease In Later Life

Scientists now understand more about why being exposed to nicotine while you were a fetus will increase your risk of developing cardiovascular disease as an adult. “We have found distinct links between cigarette smoking or even using nicotine patches or gum and the long-term harm for the child,” says Dr. DaLiao Xiao, a scientist who works at the Loma Linda University School of Medicine in California.

Publishing his research in the British Journal of Pharmacology, Xiao showed that when he gave nicotine to pregnant rats, the offspring had higher risks of high blood pressure than animals whose mothers didn’t receive nicotine during pregnancy. While the work was carried out in rats, these findings fitted well with studies carried out in people.

Importantly, Xiao and his colleagues have discovered that specific changes in the blood vessel walls account for this outcome. Xiao shows that nicotine causes the formation of chemicals, known as reactive oxygen species (ROS), in the walls of blood vessels in the fetus. These ROS cause permanent changes that alter the normal behaviour of the blood vessel. This faulty programming is then carried throughout the individual’s life and may lead to high blood pressure in adults.

“Other researchers have shown that cigarette smoking or nicotine use in pregnant women results in an increased risk of hypertension and cardiovascular disease in adulthood. Our findings provide novel information of the fetal programming that links fetal nicotine exposure to the long term damage,” says Xiao.

In a commentary accompanying the paper, Associate Professor Christopher Sobey, of the Department of Pharmacology, Monash University, Australia, states, “If this is ultimately proven in humans, this important work will have revealed a novel cardiovascular risk factor that can only be modified before birth.”

Vegetarian Diet May Protect Against Common Bowel Disorder

Research: Diet and risk of diverticular disease in Oxford cohort of European Prospective Investigation into Cancer and Nutrition (EPIC): prospective study of British, vegetarians and non-vegetarians.

Vegetarians are a third less likely to get a common bowel disorder (diverticular disease) than their meat eating counterparts, finds a new study published on bmj.com.

Diverticular disease has been termed a “disease of western civilisation” because of the higher numbers of cases in countries like the UK and the US compared with parts of Africa. The condition affects the large bowel or colon and is thought to be caused by not consuming enough fibre. Typical symptoms include painful abdominal cramps, bloating, wind, constipation and diarrhoea.

Previous research has suggested that a low fibre diet could lead to diverticular disease, and that vegetarians may have a lower risk compared with meat eaters, but there is little evidence to substantiate this.

So Dr Francesca Crowe and her team from the Cancer Epidemiology Unit at the University of Oxford set out to examine the link between a vegetarian diet and intake of dietary fibre with the risk of diverticular disease.

Their findings are based on 47,033 generally health conscious British adults who were taking part in the European Prospective Investigation into Cancer and Nutrition (EPIC)-Oxford study. Of those recruited, 15,459 reported consuming a vegetarian diet.

After an average follow-up time of 11.6 years, there were 812 cases of diverticular disease (806 admissions to hospital and six deaths). After adjusting the factors such as smoking, alcohol and body mass index (BMI), vegetarians had a lower risk of diverticular disease compared with meat eaters.

Furthermore, participants with a relatively high intake of dietary fibre (around 25g a day) had a lower risk of being admitted to hospital with or dying from diverticular disease compared with those who consumed less than 14g of fibre a day.

Consuming a vegetarian diet and a high intake of dietary fibre are both associated with a lower risk of diverticular disease, say the authors. The 2000-1 UK National Diet and Nutrition Survey showed that 72% of men and 87% of women were not meeting the recommended average intake for dietary fibre of 18 g per day and so the proportion of cases of diverticular diseases in the general population attributed to a low fibre diet could be considerable, they add.

These findings lend support to the public health recommendations that encourage the consumption of foods high in fibre such as wholemeal breads, wholegrain cereals, fruits and vegetables, they conclude.

In an accompanying editorial, researchers from Nottingham University Hospital discuss the implications for the health of the population and the individual.

Based on these findings, David Humes and Joe West estimate that “about 71 meat eaters would have to become vegetarians to prevent one diagnosis of diverticular disease.”

They add: “Overall the opportunity for preventing the occurrence of diverticular disease and other conditions, such as colorectal cancer, probably lies in the modification of diet, at either a population or an individual level.” However, they stress that “far more evidence is needed before dietary recommendations can be made to the general public.”

Over Half Of Alzheimer’s Cases May Be Preventable, Say Researchers

Over half of all Alzheimer’s disease cases could potentially be prevented through lifestyle changes and treatment or prevention of chronic medical conditions, according to a study led by Deborah Barnes, PhD, a mental health researcher at the San Francisco VA Medical Center.

Analyzing data from studies around the world involving hundreds of thousands of participants, Barnes concluded that worldwide, the biggest modifiable risk factors for Alzheimer’s disease are, in descending order of magnitude, low education, smoking, physical inactivity, depression, mid-life hypertension, diabetes and mid-life obesity.

In the United States, Barnes found that the biggest modifiable risk factors are physical inactivity, depression, smoking, mid-life hypertension, mid-life obesity, low education and diabetes.

Together, these risk factors are associated with up to 51 percent of Alzheimer’s cases worldwide (17.2 million cases) and up to 54 percent of Alzheimer’s cases in the United States (2.9 million cases), according to Barnes.

“What’s exciting is that this suggests that some very simple lifestyle changes, such as increasing physical activity and quitting smoking, could have a tremendous impact on preventing Alzheimer’s and other dementias in the United States and worldwide,” said Barnes, who is also an associate professor of psychiatry at the University of California, San Francisco.

The study results were presented at the 2011 meeting of the Alzheimer’s Association International Conference on Alzheimer’s Disease in Paris, France, and published online on July 19, 2011 in Lancet Neurology.

Barnes cautioned that her conclusions are based on the assumption that there is a causal association between each risk factor and Alzheimer’s disease. “We are assuming that when you change the risk factor, then you change the risk,” Barnes said. “What we need to do now is figure out whether that assumption is correct.”

Senior investigator Kristine Yaffe, MD, chief of geriatric psychiatry at SFVAMC, noted that the number of people with Alzheimer’s disease is expected to triple over the next 40 years. “It would be extremely significant if we could find out how to prevent even some of those cases,” said Yaffe, who is also a professor of psychiatry, neurology and epidemiology at UCSF.

Another Danger Of Secondhand Smoke — Hearing Loss

NEW YORK, July, 18, 2011 – NYU School of Medicine researchers report in a new study that exposure to tobacco smoke nearly doubles the risk of hearing loss among adolescents. The study is published in the July, 2011, issue of Archives of Otolaryngology – Head & Neck Surgery.

“More than half of all children in the U.S. are exposed to secondhand smoke, so our finding that it can lead to hearing loss in teenagers has huge public health implications,”* says Anil Lalwani, MD, professor of professor of otolaryngology, physiology and neuroscience, and pediatrics at NYU School of Medicine, who led the research. “We need to evaluate how we deal with smoking in public places and at home, as well as how often and when we screen children for hearing loss,” he says.

The dangers of secondhand smoke are well known. Living with a smoker raises the risk of dying from heart disease and lung cancer, and in children exposure to smoke exacerbates the severity of asthma attacks and causes more than 750,000 middle ear infections, according to the American Cancer Society. The new study is the first to link secondhand smoke to hearing loss.

More than 1,500 teenagers aged 12 to 19 participated in the nationwide study. They were selected from the 2005-2006 National Health and Nutrition Examination Survey, which collects health information from children and adults around the United States. The teenagers were initially evaluated in their homes and then were given extensive hearing tests and blood tests for the chemical cotinine, a metabolite of nicotine, at a medical center.

The teens exposed to secondhand smoke, as measured by the metabolite in their blood, were more likely to have sensorineural hearing loss, which is most often caused by problems with the cochlea, the snail-shaped hearing organ of the inner ear. “It’s the type of hearing loss that usually tends to occur as one gets older, or among children born with congenital deafness,” explains co-author Michael Weitzman, MD, professor of pediatrics and psychiatry at NYU School of Medicine.

The study found that teenagers exposed to smoke performed worse across every sound frequency tested, especially mid-to-high frequencies important for understanding speech. In addition, teenagers with higher cotinine levels, indicating greater exposure, were more likely to have one-sided–or unilateral–low-frequency hearing loss. Overall, the researchers conclude that their findings indicate that “tobacco smoke is independently associated with an almost 2-fold increase in the risk of hearing loss among adolescents.”

Over 80 percent of the affected teenagers in the study were not aware of any problem, the researchers reported. “Milder hearing loss is not necessarily noticeable,” says Dr. Lalwani. “Thus, simply asking someone whether they think they have hearing loss is insufficient.”

The consequences of mild hearing loss, which researchers suspect may be due to damage to the ear’s delicate blood supply, are “subtle yet serious,” says Dr. Weitzman. Affected children can have difficulty understanding what is being said in the classroom and become distracted. As a result, they may be labeled as “troublemakers” or misdiagnosed with ADHD (attention deficit hyperactivity disorder).

Currently, all infants born in the United States are screened for hearing loss; however, there are no guidelines for screening a child’s hearing past the early school years, says Dr. Lalwani. “Those children who are exposed to secondhand smoke,” he says, “need to be regularly screened.”

Seaweed As A Rich New Source Of Heart-Healthy Food Ingredients

In an article that may bring smiles to the faces of vegetarians who consume no dairy products and vegans, who consume no animal-based foods, scientists have identified seaweed as a rich new potential source of heart-healthy food ingredients. Seaweed and other “macroalgae” could rival milk products as sources of these so-called “bioactive peptides,” they conclude in an article in ACS’s Journal of Agricultural and Food Chemistry.

Maria Hayes and colleagues Ciarán Fitzgerald, Eimear Gallagher and Deniz Tasdemir note increased interest in using bioactive peptides, now obtained mainly from milk products, as ingredients in so-called functional foods. Those foods not only provide nutrition, but have a medicine-like effect in treating or preventing certain diseases. Seaweeds are a rich but neglected alternative source, they state, noting that people in East Asian and other cultures have eaten seaweed for centuries: Nori in Japan, dulse in coastal Europe, and limu palahalaha in native Hawaiian cuisine.

Their review of almost 100 scientific studies concluded that that some seaweed proteins work just like the bioactive peptides in milk products to reduce blood pressure almost like the popular ACE inhibitor drugs. “The variety of macroalga species and the environments in which they are found and their ease of cultivation make macroalgae a relatively untapped source of new bioactive compounds, and more efforts are needed to fully exploit their potential for use and delivery to consumers in food products,” Hayes and her colleagues conclude.
Reference
Fitzgerald C, Gallagher E, Tasdemir D, Hayes M. Heart Health Peptides from Macroalgae and Their Potential Use in Functional Foods. J Agric Food Chem 2011; 59 (13): 6829–36.

 

 

Does Food Act Physiologically Like A ‘Drug Of Choice’ For Some?

Reducing variety in food choices may represent an important strategy for those trying to lose weight.

Variety is considered the “spice of life,” but does today’s unprecedented level of dietary variety help explain skyrocketing rates of obesity? Some researchers think it might.

According to ASN Spokesperson Shelley McGuire, PhD: “We’ve known for years that foods- even eating, itself- can trigger release of various brain chemicals, some of which are also involved in what happens with drug addiction and withdrawal. And, as can happen with substance abusers, tolerance or “habituation” can occur, meaning that repeated use (in this case, exposure to a food) is sometimes accompanied by a lack of response (in this case, disinterest in the food). The results of the study by Epstein and colleagues provides a very interesting new piece to the obesity puzzle by suggesting that meal monotony may actually lead to reduced calorie consumption. The trick will be balancing this concept with the importance of variety to good nutrition.”

Studies have shown that many people become disinterested in a particular food when they are repeatedly exposed to it. This response, called habituation, can decrease caloric intake in the short-run. Conversely, when presented with a variety of foods, caloric intake can increase. The “food addiction hypothesis” purports that some people may overeat because they are insensitive to the normal habituation response and thus need even more exposure to a food to trigger a disinterest. However, there has been no rigorous research investigating whether healthy-weight and overweight individuals have different habituation responses, and little is known about what patterns of food exposure are most powerful in triggering habituation. To help close these research gaps, researchers studied long-term habituation in obese and nonobese women. Their results, and an accompanying editorial by Nicole Avena and Mark Gold, are published in the August 2011 issue of The American Journal of Clinical Nutrition.

Sixteen nonobese [BMI (in kg/m2) < 30] and 16 obese (BMI  30) women were randomly assigned to 1 of 2 groups: the “weekly group” participated in weekly experimental food exposure sessions for 5 wk, whereas the “daily group” were studied daily for 5 consecutive days. During each 28-min experimental session, subjects were asked to complete a variety of tasks after which they were “rewarded” by being given a 125-kcal portion of macaroni and cheese. Participants could work for as much food as they wanted. The researchers then evaluated total energy intake.

Whereas weekly food exposure increased total caloric intake by approximately 30 kcal/d, daily exposure decreased energy consumption by ~100 kcal/d. This supports long-term habituation in terms of caloric intake. Very few differences were found between how obese and nonobese individuals responded.

The authors concluded that reducing variety in food choices may represent an important strategy for those trying to lose weight. Moreover, having a person even remember that they have eaten a certain food recently may be effective in this regard. In their accompanying editorial, Avena and Gold compare physiologic components of the food addiction hypothesis to the body’s addictive responses to drugs. They also ponder whether school-lunch planners and public health officials should note that diversity in the menu is not necessarily a virtue” but might instead “be associated with promoting excess food intake and increased body mass index.” Provocative food for thought.

 

Reference

Epstein LH, Carr KA, Cavanaugh MD, Paluch RA, Bouton ME. Long-term habituation to food in obese and nonobese women. Am J Clin Nutr 2011; 94: 371–6.

High Folate Intake Linked to Better Grades in Swedish Teens

Swedish teenagers who are deficient in folate have poorer grades than teens who have a high folate intake, according to new research published online July 11 in Pediatrics.

Nilsson TK, Yngve A, Böttiger AK, Hurtig-Wennlöf A, Sjöström M.High Folate Intake Is Related to Better Academic Achievement in Swedish Adolescents.  Pediatrics. 2011 Jul 11. [Epub ahead of print].

 

ABSTRACT

Background: Adolescents are vulnerable to increased plasma total homocysteine (tHcy) and to insufficient folate status. Folate status and Hcy metabolism are linked to cognitive functions, but academic achievement by adolescents has not been studied in this respect.

Objective: To assess a possible link between academic achievement in adolescents and tHcy and its determinants, dietary folate intake, MTHFR 677 TT homozygosity, and socioeconomic status (SES).

Subjects and Methods: A study of 386 Swedish adolescents aged 15 years in whom plasma tHcy and MTHFR 677C →T genotype were assayed. The sum of school grades in 10 core subjects obtained in the final semester of compulsory 9 years of schooling was used as outcome measure of academic achievement. Lifestyle and SES data were obtained from questionnaires.

Results: Academic achievement was strongly correlated to tertiles of tHcy (negatively; P = .023) and to tertiles of folate intake (positively; P < .001). Other significant predictors were gender, smoking, and SES (proxied by school, mother’s education, and father’s income). When these were controlled for, tertiles of folate intake (P < .002) but not tertiles of tHcy (P = .523) or MTHFRgenotype remained significantly related to academic achievement.

Conclusion: Folate intake had a positive association with academic achievement in the 15-year-olds, which was not attenuated by SES or MTHFR677 TT homozygosity. These results provide new information that points to the importance of keeping a closer watch on folate status in childhood and adolescence. They may also have direct implications for school meal provisions, school teaching programs, and information to parents.

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