Safarina G Malik, a senior researcher Eijkman Institute of Molecular Biology, and his team were studying human evolution that occurred in Bali, which is suspected to change more fat. He observed several parameters such as markers of obesity Body Mass Index (BMI), abdominal circumference (WC), Blood Sugar, and Fasting Glucose (FPG).
Body mass index is a parameter that is used to classify humans in the category of underweight, normal or excessive. The index is obtained by multiplying body weight by height squared per hundred.
The study was conducted in four places that represent rural and urban areas. Legian area represents the urban area while the area Pedawa, Penglipuran and Nusa Ceningan be a representation of rural areas. The four areas were chosen because the original Balinese village.
The results Bali urban designation that humans fatter. "The Balinese urban although young age but have a high BMI. This means they are more obese, "said Safarina.
Balinese urban BMI of 26 while the Balinese countryside by 23. For Asians, the number 25 is sacred number. When BMI exceeds that number, then someone is said to be overweight.
In addition to BMI, abdominal circumference urban Balinese man is greater than the Balinese countryside. Noted, the Balinese urban abdominal circumference is 89 - / + 11 while the Balinese countryside is a 80 - / + 11. The amount of abdominal circumference refer to the accumulation of fat in the area.
So far, although BMI and large WC, blood sugar and fasting blood sugar in humans have not shown an increase in urban Bali significant.
"But, judging from the triglycerides and HDL (High Density Lipoprotein), the Balinese urban began to look unhealthy. Their high triglycerides and low HDL her, "he added when met Kompas.com Safarina Friday (12/23/2011) then.
Triglycerides are fats, composed of fatty acids and glycerol. High triglyceride levels could have an impact on the accumulation of fat in blood vessels and other tissues. HDL is often known as good cholesterol, contributing to clean fatty deposits in blood vessels. With the decrease in HDL, the less effective the cleaning function.
Overweight and environmental construction
According Safarina, obesity is found in urban humans need to be observed. Obesity can occur due to changes in environment and lifestyle which in turn raises the pressure so as to give effect to humans genetically, accelerated the process of evolution.
This is related to a theory called niche construction. The theory is still widely debated putting these men not only as a helpless object of natural selection and evolution, but an active subject to change until it affects the environment itself.
"If the normal evolution, it's affect on the environment and natural selection, change the gene pool and evolved into a culture and passed down continuously. If niche construction, gene pools and cultures can come back again to change the environment, and can be lowered again, "said a graduate of Monash University, Australia.
Some evidence for the theory of niche construction can be seen. Such as the appearance of genes that play a role in the absorption of milk lactose. People living in the Mediterranean, has a cultural breeding and milking, developed a gene which specifically supports the absorption of lactose. In other populations, this gene is active only when the human infant breast milk and consume. However, in Mediterranean societies, this gene is maintained into adulthood due to keep drinking milk.
Other evidence is the sickle-cell anemia or red blood cells that have mutated so that the crescent-shaped. Mutation is not happening without a cause. At first, the mutation occurs because African societies began to develop agriculture. Agricultural development triggers the next puddle rice fields where the development potential as larva Malaria-carrying mosquitoes. Mutation should be done so that people survived the death and extinction due to the disease until later developed sickle-cell anemia are resistant to malaria.
In Bali, niche construction is also happening with the development of water temples and irrigation system called subak. The system according to the existing inscription (Bebetin and Sukawana) has developed since 1,000 years ago. The system creates stability because it can guarantee the availability of water so that agriculture can be done. In addition, the subak system also creates genetic stability, human Bali in particular has a genetic background suitable for his lifestyle as a farmer.
However, the change is beginning to occur. Bali's new environmental construction has taken place. Bali's economy which was originally supported by the rice fields are now supported by the hotels and exotic beaches. Luxury resort is built up to the villages. Agricultural land is converted into a luxury resort. And, the most conspicuous place in Legian, where the rice is almost nothing left, turned into a hotel and nightclub.
"The most changed is the people in the area of tourism, such as Legian. They are used typically to the fields or the sea, not now. Their lifestyle change. Now so more to sit in the shop waiting for a buyer, "explains Safarina.
Is the obesity that occurs in humans Bali urban niche construction is the result? Could be. However, this conclusion remains to be investigated further and could not be done in the blink of an eye. Genetic changes always take place later so that their impact can only be seen hundreds or thousands of years. In addition, large numbers of samples are needed to see it.
Some genetic evidence
Although there are several obstacles such as a long study period and the number of samples, the research is still being done. Aspects examined genetic causes of obesity.
The research team examined 10 genes that become a risk factor for obesity. Of the 10 genes, two of which are UCP2 and ADRB3. UCP2 gene is associated with insulin secretion while ADRB3 associated with weight gain. Both are also a risk factor for the emergence of Type 2 Diabetes Mellitus (T2DM).
For UCP 2, seen a single base change Ala55Val and G (-866) A, which is usually associated with obesity. Based on the results of a study that will soon be published, polymorphisms in genes that affect the prevalence of obesity. For example, a single base change in G (-866) A is associated with high triglyceride levels in men. In women, there is an association between a single base change in the prevalence of type 2 diabetes mellitus.
Meanwhile, the study looked at the effects on the ADRB3 Arg64 and Trp64 alleles with obesity. The results showed that the Arg64 allele effect on obese women living in rural areas, and Penglipuran Pedawa. Still, can not be said too that these alleles had no effect in urban areas. Genetic effects in the city may be slightly blurred because of the many factors that affect the human environment.
In a study published in the journal ADRB3 BMC Research Notes in 2011, it appears also that the Arg64 allele is also associated with the prevalence of metabolic syndrome, including an increase in WC, FPG and HDL. As many as 45 percent of men who have the metabolic syndrome in urban areas have alleles that.
The results of published studies can be said to be the initial symptom. Research with larger sample size remains to be done to confirm that the process is happening right now is a form of niche construction. Moreover, still need to be carried out checks on neutral marker owned. Examination of a neutral marker itself is planned to begin next year.
Health challenges
Regardless of whether the process that occurs is a niche construction or not, humans change urban Bali can not be denied. Studies show that obesity in Bali urban areas doubled from rural areas. It demands attention. Obesity can lead to the emergence of diabetes mellitus, cardiovascular disease and fatty liver.
Therefore, it is necessary to educate the people of Bali to have a healthy lifestyle. For example by eating healthy foods. If not, heart disease, sugar and hearts will be increasingly common in Bali.
"Genetic background of people of Bali are still farming. Not suitable if you eat fast food like the western or rice which are numerous, "said Safarina a joint team of researchers at the Eijkman has expertise in the field of mitochondrial DNA, the DNA contained in the cell organelles that contribute to produce energy. According to him, the composition of the human diet should consist of many Balinese vegetables, fruit and rice to taste.
Changes become more obese is not only found in Bali. In countries that have industrialized first, the change has occurred. Education about diet and lifestyle in a condition which makes them more able to adjust the current.
Meanwhile, another concern should also be given subak that has existed since thousands of years ago. When the number of subak dwindle due to be converted into a place or facility that will support tourism, the Balinese will face the challenge of food, drought and shortage of drinking water. Ultimately, this will force the people of Bali are also genetically changed, evolved. Unfortunately, evolution does not occur in a short time, take place within a period of thousands of years. And, the evolution was painful.
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