Species-Specific Microbes May Be Key to a Healthy Immune System
(Mice raised with human microbiomes never develop mature immune systems, which may explain the rise in immunological illnesses).
Mice have a jungle of bacteria, viruses and fungi in their stomachs-and so do we. These microorganisms help both mice and us break down dinner. As we are finding, these bugs also help to regulate the immune system. But we are just starting to learn how these tiny organisms influence us and how changing their composition changes us.
In an attempt to find out, postdoctoral researcher Hachung Chung and her colleagues at Dennis Kasper's Lab at Harvard Medical School tried raising mice with exclusively human gut microbiota. The human microbes did pretty well in the mice guts. Interestingly, though, the mice with these microbes did not: their immune systems remained underdeveloped. Even when researchers gave rat microbiota to mice, the mice's immune systems failed to mature. The results were published in the June 22 issue of Science.
The findings are "perhaps the most definitive that I've seen," says Eugene Chang, a professor of medicine at the University of Chicago. They show "the critical and specific relationship between host and gut microbes, which is needed for proper development of the host immune response," he says.
The results support the thinking that we humans have coevolved with our microbes-and we're probably not the same without them. "The selection of partners is not by chance," Chang says. And that might explain why as we alter our microbiomes-with antibiotics and super-clean upbringings-our immune systems have been changing as well, ushering in increasing rates of autoimmune conditions such as allergies and diabetes. "The consequence is that the balance between us and our microbes, determined through evolution, is upset in ways that impact our health and increase risk for many diseases that were previously uncommon," he notes.
Scientific American | June 23, 2012
Caffeine in coffee may delay onset of Alzheimer's disease
Previous studies have suggested that caffeine/coffee protects against Alzheimer's disease. A case control study published in the Journal of Alzheimer's Disease by Cao et al monitored the cognitive status of 124 people aged between 65 and 88 with mild cognitive impairment (MCI), an early sign of Alzheimer's disease. The researchers from University of South Florida and University of Miami note that many participants were expected to develop Alzheimer's within a few years. Using compete ELISA kits, plasma caffeine concentrations were measured. Over 2-4 years the participants were monitored for cognitive status. Cao et al found that blood levels of caffeine were more than 50% lower among people with MCI who developed Alzheimer's during follow-up, when compared with their counterparts who did not worsen. No MCI patients with a blood caffeine level above 1,200 ng/ml developed the disease over the 2-4 year period. They report that coffee was the main or only source of caffeine among people in the study. Cao et al suggest a reason why caffeine may help delay the development of Alzheimer's, reporting that it involves beta-amyloid. This is a protein that accumulates in the brain of people with the disease. The authors state that this protein is in our brains from birth however as we age, the protein accumulates or aggregates in the brain because it is no longer sufficiently metabolised. Cao et al suggest that the "system can't handle all of it and leftover protein accumulates in the brain." The study reports that caffeine inhibits the production of beta-amyloid, so the body can metabolise all of the available protein. Dr Cao is quoted by the popular press as saying: "These intriguing results suggest that older adults with mild memory impairment who drink moderate levels of coffee -- about 3 cups a day -- will not convert to Alzheimer's disease -- or at least will experience a substantial delay before converting to Alzheimer's."
RSSL Food e-News 542: 6 - 20 June 2012
POSTMENOPAUSAL WOMEN SHOULD NOT TAKE VITAMIN D, CALCIUM SUPPLEMENTS
The U.S. Preventive Services Task Force has issued a draft statement recommending that healthy postmenopausal women should not take low doses of calcium or vitamin D supplements to prevent fractures.
The group, an independent panel of experts in prevention and primary care appointed by the federal Department of Health and Human Services, also considered use of the supplements by healthy premenopausal women and men. For those groups, it said, there was insufficient evidence to recommend taking vitamin D with or without calcium to prevent fractures.
In addition, the panel said there is insufficient evidence as to whether the supplements prevent cancer. The cancer studies included ones testing the supplements to prevent all cancers as well as ones asking about colorectal cancer, prostate cancer, and breast cancer.
Their analysis of the effects of the supplements included 137 studies, including randomized controlled trials. The low doses that the group referred to, at least for the postmenopausal women, were a typical level of 400 international units or less of vitamin D a day and 1,000 mg or less of calcium. The group concluded that at that dose there is sufficient evidence to say they don't prevent fractures. In fact, there is a small risk that taking the supplements may cause kidney stones.
IFT Weekly 13 June 2012.
ASSOCIATION OF URINARY BISPHENOL A CONCENTRATION WITH HEART DISEASE: EVIDENCE FROM NHANES 2003/06
Bisphenol A (BPA) is a high production volume chemical widely used in food and drinks packaging. Associations have previously been reported between urinary BPA concentrations and heart disease, diabetes and liver enzymes in adult participants of the National Health and Nutrition Examination Survey (NHANES) 2003/04.
We aimed to estimate associations between urinary BPA concentrations and health measures in NHANES 2005/06 and in data pooled across collection years.
A cross-sectional analysis of NHANES: subjects were n = 1455 (2003/04) and n = 1493 (2005/06) adults aged 18-74 years, representative of the general adult population of the United States. Regression models were adjusted for age, sex, race/ethnicity, education, income, smoking, BMI, waist circumference, and urinary creatinine concentration. Main outcomes were reported diagnoses of heart attack, coronary heart disease, angina and diabetes and serum liver enzyme levels. Higher BPA concentrations were associated with coronary heart disease in 2005/06 (OR per z-score increase in BPA = 1.33, 95%CI: 1.01 to 1.75, p = 0.043) and in pooled data (OR = 1.42, CI: 1.17 to 1.72, p = 0.001).
Higher BPA exposure, reflected in higher urinary concentrations of BPA, is consistently associated with reported heart disease in the general adult population of the USA. Studies to clarify the mechanisms of these associations are urgently needed.
PLoS ONE 5(1): e8673. doi:10.1371/journal.pone.0008673. 2012.
BEVERAGES WITH LEMON, BERRIES MAY PRESERVE HEALTHFUL BIOACTIVE COMPOUNDS
A study published in the Journal of Food Science examined the use of lemon juice and berries to develop new functional beverages with a prolonged preservation of bioactive compounds throughout storage.
Considering the health potential of lemon and berry fruits, the researchers developed different functional beverages rich in antioxidant phytochemicals. Lemon juice was combined with two different concentrates-elderberry and grape-in a proportion of 5% (w/v). Bioactive composition (flavonoids and vitamin C) and color stability, as well as the antioxidant capacity of the mixtures, during a period of 56 days of storage, were studied.
The researchers found that the anthocyanins played a protective role on ascorbic acid preservation in both the lemon berry blends, keeping vitamin C stable until the end of the storage. They found that the beverage combining lemon and elderberry performed better than the grape and lemon mixture in terms of health-promoting phytochemicals content.
IFT Weekly May 23, 2012.
RESEARCHERS EXAMINE IMPORTANCE OF HUMAN BREAST MILK COMPONENT
A study published in the Journal of Nutrition shows that human milk oligosaccharides, or HMO, produce short-chain fatty acids that feed a beneficial microbial population in the infant gut. In addition, the study shows that the bacterial composition adjusts as the baby grows older and its needs change.
Even though HMO are a major component of human milk, present in higher concentration than protein, many of their actions in the infant are not well understood. Furthermore, they're virtually absent from infant formula. The researchers wanted to find out what formula-fed babies were missing.
In the study, breast milk was obtained from mothers of preterm infants at Chicago's Rush University Medical Center, and the HMO were isolated and analyzed. The scientists tested bacteria from 9- and 17-day-old sow-reared and formula-fed piglets. Because piglets grow so rapidly, these ages reflect approximately three- and six-month-old human infants.
IFT Weekly Newsletter May 16 2012.
BREAD CONSUMPTION AND ADIPOSITY
Bautista-Castano and Serra-Majem assessed eating patterns that include bread and their association with overall obesity or excess abdominal adiposity - this was to investigate the long-standing belief held by the general public that bread fattens. A review was done on 38 epidemiological studies that fulfilled the inclusion criteria (22 cross-sectional, 11 prospective cohort, and five intervention). The results indicate that dietary patterns that include whole-grain bread do not positively influence weight gain and may be beneficial to ponderal status. As for eating patterns that include refined bread, the majority of cross-sectional studies indicate beneficial effects, while most of the well-designed cohort studies demonstrate a possible relationship with excess abdominal fat. The preliminary results necessitate further studies that focus specifically on bread consumption, within different dietary patterns, and its influence on ponderal status.
ILSI SEA News Flash 2012.
The abstract by Bautista-Castano and Serra-Majem (2012) is available on the following link:
GUT FLORA, HIGH-FAT DIET AND METABOLIC DISORDERS
A diet rich in greasy foods causes an imbalance in our gut flora. The composition of gut flora seems to determine the way in which the body develops certain metabolic disorders such as diabetes, regardless of any genetic modification, gender, age or specific diet, according to research published in GUT (International Journal of Gastroenterology and Hepatology). Gut flora, otherwise known as gut microbiota, are the bacteria that live in our digestive tract. There are roughly one thousand different species of bacteria that are nourished partly by what we eat. Each person has their own specific gut flora and metabolism, and these differ according to our dietary habits. To determine whether the gut flora was the cause or the result of metabolic disorders, the team directly modified the gut flora of a group of mice by adding dietary fibres and gluco-oligosaccharides to their high-fat diet. By adding these fibres, most of the physiological characteristics were modulated. The metabolism of the mice that were treated with these fibres was similar to that of the thin, non-diabetic mice, but the gut flora of the mice treated with fibres changed greatly to that of the other phenotypes observed.
RSSL Food e-news. Edition 539: 25 April - 9 May 2012.
Snippets - contributions are welcome. Edited and produced by Dr. B Cole. - firstname.lastname@example.org / Fx 011 660 6444 with the help of the Northern Branch Committee.