Bereiding van voedsel net zo belangrijk als voedsel zelf.*
Door het voedsel te koken, stomen, smoren en zo min mogelijk te bakken, grillen of frituren kunnen we veel gezonder oud worden blijkt uit een studie. De goede manieren van bereiding voorkomen een teveel aan AGE’s (advanced gycation end products) in het menselijk lichaam. AGE’s komen vrij door reacties van suiker, eiwitten en bepaalde vetten. Als de voeding bij hoge temperaturen in afwezigheid van water gebakken wordt stijgt hun aantal fors. Ook bij sterilisatie en pasteurisatie en andere manieren van bereiding van kant en klare voeding worden AGE’s geproduceerd. Hoe meer AGE’s in het menselijke lichaam aanwezig zijn hoe hoger de markers voor ontstekingen en oxidatieschade. Een bepaalde hoeveelheid AGE’s kan het lichaam wel verwerken doch langdurig teveel geeft stapeling in het lichaam met nare gevolgen van dien zoals ontstekingen, diabetes, nierziektes, de ziekte van Alzheimer en hart- en vaatziektes. Zo blijken mensen van 60 jaar wel 35% meer AGE’s in het bloed te hebben dan mensen jonger dan 45 jaar. Bij het ouder worden kan het lichaam de overmatige AGE’s ook al moeilijker uit het lichaam verwijderen. Mensen met diabetes of een hartziekte blijken ook veel hogere bloedwaarden aan AGE’s te hebben. Bij eerdere dierenproeven was al vastgesteld dat dieren met een lage bloedwaarden AGE’s duidelijk ouder werden als hun soortgenoten met hogere waarden. Nu nog worden bloedwaarden AGE’s nog niet gecontroleerd maar het lijkt wenselijk dit wel te gaan doen, net zoals met cholesterol.
Het advies is zonodig af en toe eens bakken, frituren, grillen of barbecuen is geen probleem doch wel vaker stomen, koken of smoren en het eten van kant en klare voeding flink te beperken. De beste manier van vleesbereiding blijkt te zijn: het vlees eerst marineren in citroensap, azijn of andere zure oplossing en daarna bakken in een heteluchtoven, dan ontstaan de minste AGE's.
Food
Preparation May Play A Bigger Role In Chronic Disease Than Was Previously
Thought.
How
your food is cooked may be as important to your health as the food itself.
Researchers now know more about a new class of toxins that might soon become as
important a risk factor for heart disease and metabolic disorders as trans fats.
This class of toxins, called advanced glycation end products (AGEs), are
absorbed into the body through the consumption of grilled, fried, or broiled
animal products, such as meats and cheeses. AGEs, which are also produced when
food products are sterilized and pasteurized, have been linked to inflammation,
insulin resistance, diabetes, vascular and kidney disease, and Alzheimer's
disease.
A new study at Mount Sinai School of Medicine reveals that AGE levels are
elevated in the blood of healthy people, and even more so in older individuals
than in younger people. Of particular interest was the finding that a major
determinant of the blood levels of AGEs is the amount of AGEs in the diet, not
dietary calories, sugar, or fat. The study, which was done in collaboration with,
and supported by, the National Institute on Aging (NIA), is published in the Journal
of Gerontology: Medical Sciences.
"AGEs are quite deceptive, since they also give our food desirable tastes
and smells," says Helen Vlassara, MD, senior study author, Director of the
Division of Experimental Diabetes and Aging, and Professor of Medicine and
Geriatrics at Mount Sinai School of Medicine. "So, consuming high amounts
of grilled, broiled, or fried food means consuming significant amounts of AGEs,
and AGEs in excess are toxic. People should be given information about their AGE
intake and be advised to consider their intake in the same way they would think
about their trans fats and salt intake. They should be warned about their AGE
levels the way they are about their cholesterol levels or cigarette
smoking."
Inflammation and oxidative stress are more common in older age, so the goal of
the study was to assess whether AGEs played a significant role in age-related
inflammation and oxidative stress by measuring AGE levels in both young and
older individuals. The study involved 172 healthy men and women who were divided
into two age groups those between the ages of 18 and 45 and those between the
ages of 60 and 80. Dr. Vlassara and her team also wanted to assess whether AGE
levels correlated with dietary intake. To do this, her team recorded the
patient's body weight, body fat, three-day dietary information, and collected
blood samples to measure biomarkers of inflammation, such as C-reactive protein
(CRP). Blood samples were used to test for two common AGEs, called
carboxymethyllysine (CML) and methylglyoxal (MG), which latch on to proteins and
fats.
The blood tests showed that AGE levels were 35 percent higher in individuals age
65 and older compared with those younger than age 45. The study also showed that
in all of the participants, the higher the consumption of foods rich in AGEs,
the higher the blood levels of AGEs, and higher the levels of CRP and other
markers of inflammation.
Much to the researchers' surprise, the study also showed that AGE levels could
be very high in young healthy people. In fact, high AGE levels found in some
healthy adults in this study were on par with AGE levels observed in diabetic
patients in their earlier studies. The fact that healthy adults had levels
similar to those seen in diabetic patients may suggest that early and prolonged
exposure to these substances in the diet could accelerate the onset of diseases.
Dr. Vlassara notes that the availability and consumption of AGE-rich foods is
high and correlates with rising rates of diabetes and heart disease.
"Excessive intake of fried, broiled, and grilled foods can overload the
body's natural capacity to remove AGEs," Dr. Vlassara notes, "so they
accumulate in our tissues, and take over the body's own built-in defenses,
pushing them toward a state of inflammation. Over time, this can precipitate
disease or early aging." Once AGEs enter the body, it becomes more
difficult to get them out, especially as people age. Older people have a reduced
capacity for removing AGEs from the body, the researchers explain, most likely
because kidney function slows down as the body ages.
As Dr. Vlassara cautions, "although the accumulation of AGEs pose an
immediate and significant health threat to the older adult population, they are
also an invisible, lingering danger especially for younger people and this needs
to be addressed. AGE levels should be shown on nutrition labels so everyone is
aware of them when buying or preparing meals and our studies explain why."
A Simple Solution: Steam, Boil, Stew
Despite the ubiquity of AGEs, Dr. Vlassara and her team offer simple, safe, and
economic solutions that echo the recommendations given concerning trans fats
watch what you eat. New methods of cooking to reduce AGE intake, particularly
steaming, boiling or making stews, can make a difference. "Keeping the heat
down and maintaining the water content in food reduces AGE levels," Dr.
Vlassara says. A 50 percent reduction in AGE intake could have a significant and
positive impact on overall health and may even help extend one's lifespan,
according to Dr. Vlassara. In other studies, the team has found that cutting AGE
intake in half, but maintaining a diet comprised of the same calories and fat,
increased the lifespan of animals when compared with animals fed their usual
diet.
At the moment, changing one's approaches to cooking is the only defense against
excessive AGE consumption. There is no routine clinical test to inform
individuals of their blood or dietary AGE levels nor established treatment to
reduce high AGE blood levels. "The concept that food-related AGE intake is
harmful is new to the general public," says Dr. Vlassara, "and
scientists are now seeing how AGE intake fits with the current trends of disease
epidemics. Hopefully, these wake-up signals, together with other gathering
evidence at the cellular and molecular level, will accelerate our efforts to
develop effective measures against excessive dietary AGEs. This issue, however,
should be dealt with as an important health hazard now, rather than later."
About The Mount Sinai Medical Center
The Mount Sinai Medical Center encompasses The Mount Sinai Hospital and Mount
Sinai School of Medicine. The Mount Sinai Hospital is one of the nation's oldest,
largest and most-respected voluntary hospitals. Founded in 1852, Mount Sinai
today is a 1,171-bed tertiary-care teaching facility that is internationally
acclaimed for excellence in clinical care. Last year, nearly 50,000 people were
treated at Mount Sinai as inpatients, and there were nearly 450,000 outpatient
visits to the Medical Center.
Mount Sinai School of Medicine is internationally recognized as a leader in
groundbreaking clinical and basic-science research, as well as having an
innovative approach to medical education. With a faculty of more than 3,400 in
38 clinical and basic science departments and centers, Mount Sinai ranks among
the top 20 medical schools in receipt of National Institute of Health (NIH)
grants.
Mount Sinai Medical Center
One Gustave Levy Place
New York, NY 10029
United States
(Mei 2007) (Opm
Uit eerdere onderzoeken is al gebleken dat ook om andere redenen de
juiste manieren van bereiding van wezenlijk belang zijn. Bij Tips
vindt u die adviezen.)