Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Genes and diet linked to risk factors for heart disease

10.10.2006
Researchers from the Jean Mayer USDA Human Nutrition Research Center (USDA HNRCA) at Tufts University and colleagues have found another link among genes, heart disease and diet. The study, published in Circulation, examined apolipoprotein A5 (APOA5), a gene that codes for a protein, which in turn plays a role in the metabolism of fats in the blood.

The results show that people who carry a particular variant of APOA5 may have elevated risk factors that are associated with heart disease, but only if they also consumed high amounts of omega-6 fatty acids in their diets.

Corresponding author Chao-Qiang Lai, PhD, a USDA-Agricultural Research Service (ARS) scientist at the USDA HNRCA, and colleagues analyzed lipid levels and dietary assessment questionnaires of more than 2,000 participants in the Framingham Heart Study and quantified their intake of different types of fats.

Omega-6 fatty acids, as well as omega-3 fatty acids, are polyunsaturated fatty acids (PUFAs) and, according to a report from the National Institutes of Health Office of Dietary Supplements, most Americans consume about 10 times more omega-6s than omega-3s. Omega-3s are found in nuts, leafy green vegetables, fatty fish, and vegetable oils like canola and flaxseed, while omega-6s are found in grains, meats, vegetable oils like corn and soy, and also processed foods made with these oils. Both omega-3s and omega-6s, known as essential fatty acids, must be consumed in the diet because they are not made by the body.

"We know that some people are genetically predisposed to risk factors for heart disease, such as elevated low-density lipoprotein levels in the blood," says Lai, "and that APOA5 has an important role in lipoprotein metabolism. We wanted to determine if certain dietary factors change the role of APOA5 in metabolizing these lipoproteins and their components, such as triglycerides."

Lai and colleagues found that approximately 13 percent of both men and women in the study were carriers of the gene variant. Those individuals that consumed more than six percent of daily calories from omega-6 fatty acids displayed a blood lipid profile more prone to atherosclerosis (hardening of the arteries) and heart disease, including higher triglyceride levels.

Jose Ordovas, PhD, senior author of the study and director of the Nutrition and Genomics Laboratory at the USDA HNRCA, notes that "previous research points to polyunsaturated fatty acids like omega-3s and omega-6s as 'good' fats, thought to reduce risk of heart disease by lowering cholesterol levels if used in place of saturated fats that are mostly found in animal sources."

Ordovas continues, "Research hasn't shown us yet if there is an optimal ratio for omega- 3s to omega-6s, or if consuming a certain amount of omega-6s might negate the benefits of omega-3s. We do know that omega-6s are necessary for the body and can be a source of healthful fat in the diet, but for the 13 percent who are carriers of the particular APOA5 gene variant, consuming fewer omega-6s in relation to omega-3s may be important, as it might help reduce the risk of developing precursors to heart disease."

The carriers of the variant who ate more than six percent of total calories from omega-6s had a 21 percent increase in triglyceride levels, as well as an approximately 34 percent elevation of certain atherogenic lipoprotein particles in the blood.

Carriers who consumed less than six percent of total calories from omega-6s did not show a significant increase in the lipid levels that are risk factors for heart disease. In contrast to omega-6s, higher consumption of omega-3s decreased triglyceride and atherogenic lipoprotein particle levels in the blood, regardless of a person's APOA5 gene variant.

Although the researchers analyzed information on several types of dietary fat, including saturated fat and monounsaturated fat, the interactions between diet and APOA5 were seen only with PUFAs, "adding evidence to the prominent role of PUFAs as modulators of genetic effects in lipid metabolism," write the authors. They go on to explain that "a more complete understanding of these factors and a thoughtful use of this information should help in the identification of vulnerable populations who will benefit from more personalized dietary recommendations."

A second study published by Ordovas, Lai, and colleagues in the Journal of Lipid Research also studied variants of the APOA5 gene in participants in the Framingham Heart Study to determine if the gene is related to atherosclerosis. The authors, including corresponding author Christopher O'Donnell of the National Heart, Lung, and Blood Institute's Framingham Heart Study, and first author Roberto Elosua, a former Fulbright-Generalitat de Cataluña fellow who works with Ordovas, found that while most variants of the APOA5 gene were not associated with carotid intimal medial thickness (IMT), a surrogate measure of atherosclerosis burden, particular gene variants were "significantly associated with carotid IMT in obese participants."

Carriers of the particular gene variants who were obese expressed the effects of the gene variant differently than carriers who were not obese, showing a greater build-up of plaque in the heart. This was true for participants who were obese regardless of fat and cholesterol levels in the blood, age, gender, smoking or diabetes status, weight-for-height and blood pressure, all factors which are thought to influence risk of heart disease. Lai notes that "although obesity is a known contributing factor to heart disease, the association was strengthened in carriers of the rare APOA5 variant who were obese."

"It may be more important for some people to make preventive dietary and lifestyle changes than others, depending on their genetic makeup," says Ordovas. "The 'bad' genotype, in this study, doesn't seem to be that bad unless it's triggered by obesity," he concludes. "The observations, while strong, should be considered with caution and confirmed in other studies. Also, the findings were restricted to a Caucasian cohort and may not be generalizable to other ethnic cohorts."

Siobhan Gallagher | EurekAlert!
Further information:
http://www.tufts.edu

More articles from Studies and Analyses:

nachricht The personality factor: How to foster the sharing of research data
06.09.2017 | ZBW – Leibniz-Informationszentrum Wirtschaft

nachricht Europe’s Demographic Future. Where the Regions Are Heading after a Decade of Crises
10.08.2017 | Berlin-Institut für Bevölkerung und Entwicklung

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

Im Focus: Fast, convenient & standardized: New lab innovation for automated tissue engineering & drug

MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems Holding GmbH about commercial use of a multi-well tissue plate for automated and reliable tissue engineering & drug testing.

MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems...

Im Focus: Silencing bacteria

HZI researchers pave the way for new agents that render hospital pathogens mute

Pathogenic bacteria are becoming resistant to common antibiotics to an ever increasing degree. One of the most difficult germs is Pseudomonas aeruginosa, a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Molecular Force Sensors

20.09.2017 | Life Sciences

Producing electricity during flight

20.09.2017 | Power and Electrical Engineering

Tiny lasers from a gallery of whispers

20.09.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>