Here’s a little more good news in understanding the mechanism of getting omega3 fatty acids into brain cells. Eat smart, think smart.
Consuming oils with high polyunsaturated fatty acid content, in particular those containing omega-3s, is beneficial for the health. But the mechanisms underlying this phenomenon are poorly known.
Researchers at the Institut de Pharmacologie Moléculaire et Cellulaire (CNRS/Université Nice Sophia Antipolis), the Unité Compartimentation et Dynamique Cellulaires (CNRS/Institut Curie/UPMC), the INSERM and the Université de Poitiers1 investigated the effect of lipids bearing polyunsaturated chains when they are integrated into cell membranes.
Their work shows that the presence of these lipids makes the membranes more malleable and therefore more sensitive to deformation and fission by proteins. These results, published on August 8, 2014 in Science, could help explain the extraordinary efficacy of endocytosis2 in neuron cells.
Consuming polyunsaturated fatty acids (such as omega-3 fatty acids) is good for the health. The effects range from neuronal differentiation to protection against cerebral ischemia3. However the molecular mechanisms underlying these effects are poorly understood, prompting researchers to focus on the role of these fatty acids in cell membrane function.
For a cell to function properly, the membrane must be able to deform and divide into small vesicles. This phenomenon is called endocytosis. Generally, these vesicles allow the cells to encapsulate molecules and transport them.
In neurons, these synaptic vesicles will act as a transmission pathway to the synapse for nerve messages. They are formed inside the cell, then they move to its exterior and fuse with its membrane, to transmit the neurotransmitters that they contain. Then they reform in less than a tenth of a second: this is synaptic recycling.
In the work published in Science, the researchers show that cell- or artificial membranes rich in polyunsaturated lipids are much more sensitive to the action of two proteins, dynamin and endophilin, which facilitate membrane deformation and fission. Other measurements in the study and in simulations suggest that these lipids also make the membranes more malleable.
By facilitating the deformation and scission necessary for endocytosis, the presence of polyunsaturated lipids could explain rapid synaptic vesicle recycling.. The abundance of these lipids in the brain could then represent a major advantage for cognitive function.
This work partially sheds light on the mode of action of omega-3. Considering that the body cannot synthesize them and that they can only be supplied by a suitable diet (rich in oily fish, etc.), it seems important to continue this work to understand the link between the functions performed by these lipids in the neuronal membrane and their health benefits.
(1) This study was conducted in collaboration with teams from the Centre Commun de Microscopie Appliquée (Université Nice Sophia Antipolis) and the Laboratoire Signalisation et Transports Ioniques Membranaires (CNRS/Université de Poitiers/Université François Rabelais de Tours).
(2) Endocytosis is the name of the process by which the cells absorb various substances present in the surrounding medium by encapsulating them in a lipoprotein membrane. Endocytosis is involved in several physiological functions.
(3) See for example prior work by the Institut de Pharmacologie Moléculaire et Cellulaire on this type of stroke: Polyunsaturated fatty acids are potent neuroprotectors; Lauritzen I, Blondeau N, Heurteaux C, Widmann C, Romey G, Lazdunski M; EMBO J. (2000) 19:1784-93.
FOLSOM, Calif., Feb. 27, 2013 /PRNewswire/ — Recent research published online by the Journal of Nutrition, found an inverse relationship between walnut consumption and risk of type 2 diabetes in two large prospective cohorts of U.S. women: the Nurses’ Health Study (NHS) and NHS II. The researchers from the Harvard School of Public Health followed 58,063 women (52–77 years) in NHS (1998–2008) and 79,893 women (35–52 years) in NHS II (1999–2009) without diabetes, cardiovascular disease, or cancer at baseline. They found two or more servings (1 serving= 28 grams) of walnuts per week to be associated with a 21% and 15% lower risk of incident type 2 diabetes before and after adjusting for body mass index (BMI) respectively.
Diabetes is estimated to affect 12.6 million women in the United States and 366 million people worldwide, and the numbers are expected to rise to approximately 552 million globally by 2030. Diet and lifestyle modifications are key components in fighting this epidemic, and recent evidence suggests that the type of fat rather than total fat intake plays an important role in the development of type 2 diabetes. Specifically, a higher level of polyunsaturated fatty acids (PUFAs), found significantly in walnuts, has been associated with a reduced risk of type 2 diabetes.
“The findings here- the kind often seen with powerful pharmaceuticals- are robust, and remarkable.”
Compared with other nuts, which typically contain a high amount of monounsaturated fats, walnuts are unique because they are rich in PUFAs which may favorably influence insulin resistance and risk of type 2 diabetes. Walnuts are different among nuts specifically in that they are uniquely comprised primarily of PUFAs and are the only nut with a significant amount of alpha-linolenic acid – the plant-based omega-3 fatty acid (2.5 grams of ALA per 1 ounce/ 28 gram serving).
Diabetes and obesity expert David Katz, MD considers walnuts to be a nutritious ingredient that should be a staple in the American diet. “Observational studies can’t prove cause and effect, but when associations are seen in large populations, and occur in a well established context- cause and effect may reliably be inferred,” states Dr. Katz. He continues, “The findings here- the kind often seen with powerful pharmaceuticals- are robust, and remarkable. They strongly indicate the importance of consuming whole foods, such as walnuts, in the fight against diabetes.”
Registered dietitian and certified diabetes educator Andrea Dunn believes this new research is good news especially considering walnuts are tasty and simple to include daily. “In this study two or more servings of walnuts per week seemed to make a difference and is so easy to incorporate,” says Dunn. She suggests adding walnuts to your morning oatmeal or yogurt, grabbing a handful as an afternoon snack or trying them as a coating for fish or as a topping to your vegetable stir-fry.
We’ll no doubt be seeing lots more recipes with walnuts after the latest news about the Mediterranean diet which features walnuts among other great foods.
For more industry information, health research and recipe ideas, visit www.walnuts.org
Media resources available:
About California Walnuts:
The California walnut industry is made up of more than 4,000 growers and more than 80 handlers. The growers and handlers are represented by two entities, the California Walnut Board (CWB) and the California Walnut Commission (CWC).
California Walnut Commission
The California Walnut Commission, established in 1987, is funded by mandatory assessments of the growers. The Commission is an agency of the State of California that works in concurrence with the Secretary of the California Department of Food and Agriculture (CDFA). The CWC is mainly involved in health research and export market development activities.
22 October 2010 Elsevier
New Study in Journal of the American Dietetic Association
Periodontitis and tooth loss. Although traditional treatments concentrate on the, a common inflammatory disease in which gum tissue separates from teeth, leads to accumulation of bacteria and potential bone bacterial infection, more recent strategies target the inflammatory response. In an article in the November issue of the Journal of the American Dietetic Association , researchers from Harvard Medical School and Harvard School of Public Health found that dietary intake of polyunsaturated fatty acids (PUFAs) like fish oil, known to have anti-inflammatory properties, shows promise for the effective treatment and prevention of periodontitis.
“We found that n-3 fatty acid intake, particularly docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), are inversely associated with periodontitis in the US population,” commented Asghar Z. Naqvi, MPH, MNS, Department of Medicine, Beth Israel Deaconess Medical Center. â€œTo date, the treatment of periodontitis has primarily involved mechanical cleaning and local antibiotic application. Thus, a dietary therapy, if effective, might be a less expensive and safer method for the prevention and treatment of periodontitis. Given the evidence indicating a role for n-3 fatty acids in other chronic inflammatory conditions, it is possible that treating periodontitis with n-3 fatty acids could have the added benefit of preventing other chronic diseases associated with inflammation, including stoke as well.â€
Using data from the National Health and Nutrition Examination Survey (NHANES), a nationally representative survey with a complex multistage, stratified probability sample, investigators found that dietary intake of the PUFAs DHA and (EPA) were associated with a decreased prevalence of periodontitis, although linolenic acid (LNA) did not show this association.
The study involved over 9,000 adults who participated in NHANES between 1999 and 2004 who had received dental examinations. Dietary DHA, EPA and LNA intake were estimated from 24-hour food recall interviews and data regarding supplementary use of PUFAs were captured as well. The NHANES study also collected extensive demographic, ethnic, educational and socioeconomic data, allowing the researchers to take other factors into consideration that might obscure the results.
The prevalence of periodontitis in the study sample was 8.2%. There was an approximately 20% reduction in periodontitis prevalence in those subjects who consumed the highest amount of dietary DHA. The reduction correlated with EPA was smaller, while the correlation to LNA was not statistically significant.
In an accompanying commentary, Elizabeth Krall Kaye, PhD, Professor, Boston University Henry M. Goldman
School of Dental Medicine, notes that three interesting results emerged from this study. One was that significantly reduced odds of periodontal disease were observed at relatively modest intakes of DHA and EPA. Another result of note was the suggestion of a threshold dose; that is, there seemed to be no further reduction in odds or periodontal disease conferred by intakes at the highest levels. Third, the results were no different when dietary plus supplemental intakes were examined. These findings are encouraging in that they suggest it may be possible to attain clinically meaningful benefits for periodontal disease at modest levels of n-3 fatty acid intakes from foods.
Foods that contain significant amounts of polyunsaturated fats include fatty fish like salmon, peanut butter, and nuts.
- Full bibliographic informationArticle: â€œn-3 Fatty Acids and Periodontitis in US Adultsâ€ by Asghar Z.
Naqvi, MPH, MNS; Catherine Buettner, MD, MPH; Russell S. Phillips, MD; Roger B. Davis, ScD; and Kenneth J. Mukamal, MD, MPH, MA.
Commentary: â€œn-3 Fatty Acid Intake and Periodontal Diseaseâ€ by Elizabeth Krall Kaye, PhD
Both appear in the Journal of the American Dietetic Association, Volume 110, Issue 11 (November 2010) published by Elsevier.