A lot has been written in recent years about blood cholesterol levels. Not all that long ago, it was thought that eating foods high in cholesterol caused you have have high blood cholesterol levels, and this in turn could lead to heart disease, heart atacks, and other heart related problems. And because of these beliefs and fears, people were encouraged to eat foods super low in fat.

The problem with that philosophy and teaching is that it was a bit too generic and broad. There are actually types of fat that are good for you. In fact, these so-called "good fats" are essential for proper nutrition and health. There are also "bad fats" however, which can be a contributing factor to health and heart related problems.

Cholesterol levels in your blood now have a similar distinction. Where once it was believed that you need to have your total cholesterol levels below a certain number - such as 200mg - now it's becoming clear through scientific studies and research that this isn't always a good measuring stick. Instead, there is "good" and "bad" cholesterol. And those numbers are what's important, along with the ratio of one to another.

LDL cholesterol is considered the "bad" type, and that stands for low-density lipoprotein. Without going into a lot of medical and scientific terminology, let's suffice it to say that LDL cholesterol can have harmful reactions in the human body. In contrast, there's HDL, or high-density lipoprotein, which creates beneficial reactions in the human body.

If you find it difficult to remember which one is supposed to better and which isn't, think of LDL cholesterol as the one you want to keep low - use the L at the beginning as a reminder trigger - and HDL is the one you want to keep higher (H=Higher). The ratio between your LDL and HDL cholesterol levels is important too.

Now unfortunately testing is still a bit imprecise. In some cases, medical professionals will still do a general cholesterol test which gives you the overall levels. It's becoming more common though, to at least estimate the LDL to HDL cholesterol ratios, or total cholesterol to HDL levels, but both of these are estimates instead of actual measurements.

Some say that LDL levels should fall at or below 100mg, while newer recommendations are calling for less than 70mg. When total cholesterol to HDL is measured, it's said a 5:1 ratio or less is best.

Now you can get cholesterol from foods. Primary sources of cholesterol are from animal products such as eggs, peanuts, flax seeds, and beef. Some cholesterol can be found in plants as well, but it's usually a much smaller amount. Most people assume - and books even teach - that there is no cholesterol in plants at all. This is a misunderstanding however, because the American FDA does not require it to be on food labels if there is less than 2mg per serving.

Keep in mind though, that eating foods which contain cholesterol does not mean you'll automatically have cholesterol related health problems. Some of these problems can be caused by - or at least contributed to - by poor eating habits in general, poor exercise, and genetics.

Cholesterol levels can be hereditary. Like many health problems today, it's been found that some genetic backgrounds have much higher risks for certain health problems than others do.