Cholesterol levels can be hereditary. Many healthy people have high cholesterol levels just because they were born with the gene that causes it. Technically your Ldl would be considered borderline high. The Hdl is 81 which is an excellent level and any Hdl that is over 60 mg/dl will give you some protection against heart disease. The best ways to lower cholesterol are eating a heart-healthy diet, lifestyle changes, getting regular physical activity , avoiding tobacco smoke and medication as a last resort. Your doctor has most likely assessed all of your other risk factors and put you in to a low risk category. You already eat a healthy diet and exercise regularly, your not overweight and you are a woman. Providing you don't smoke cigarettes, don't have high blood pressure or have any other illnesses such as diabetes then your doctor most likely feels as though you are not in a high risk category.
Anyone who's total cholesterol is between 200 and 239 is technically in the borderline high category. Your Hdl is excellent your triglycerides are excellent and it all balances out. This is why your doctor did not put you on medications but he should keep an eye on you to see if anything changes. You can't change anything hereditary and if your Ldl is being caused by hereditary factors there is not a whole lot you can do about it. Some of the good foods you can eat to lower your Ldl and not your Hdl are oatmeal, fish for omega 3 fatty acids, and nuts. There is controversy about soy but it is proven that it does lower Ldl by up to 3 %. If you would like to read about these products and how much you need daily please click on this link:
I hope this has helped to answer your question. You are already on the right track with exercising and eating healthy. If you try eating some of the foods that have been shown to lower Ldl it may help you. If it gets to high or the Hdl drops and the triglycerides increase your doctor may want you to take a cholesterol medication.
Good luck and if you have any further questions please let me know
Some studies have shown that identical twins are not as 'identical' as was once thought. Differences in diet, exercise habits, environmental factor and even emotional factors as you were growing up most likely played a big role. Although you eat the same and both exercise she still lives in a different environment than you. Scientists have studied the brains of identical twins and found that upon close examination they look different. The subtle changes and environmental factors can play a big role in over all health.
There have been other studies that have shown that twins who are on the same diet will have very similar cholesterol levels. They did the research by putting them on 6 week diets, one twin would have the healthy diet and the other one would not. They would measure their levels regularly. They noticed that during each specific diet period both twins would have nearly equal correlations.
I can certainly understand your confusion with so much conflicting research. Since you don't live together there are probably environmental factors that affect both of you differently. It is hard to say but although she eats the same as you she may eat less of one thing and more of the other. It is interesting and the research is quite interesting as well. I wish I had a more definitive answer for you but I think even the scientists who study this are somewhat conflicted.
I am attaching 2 web-sites that I found that you may find interesting. I hope that this has helped clear things up a bit and again I am sorry there is no definitive answer.
Good luck and if you have any further questions please let me know.