There are reports
that the nation’s top nutrition advisory panel, the Dietary Guidelines Advisory Committee, will call to eliminate the longstanding limits on dietary cholesterol (1,2). The Committee’s decision will be used by the U.S. Department of Agriculture and the Department of Health and Human Services to create the Dietary Guidelines for Americans, 2015 that will be released this fall.
Cholesterol has been deemed an ingredient to watch and avoid
in the United States since about 1961 when it first appeared in the American Heart Association guidelines (2). The U.S. government followed suit and currently recommends no more than 300 mg of cholesterol intake per day.
The change in sentiment about cholesterol has gotten a lot of people talking.
The conversation is that nutrition and food science is too hard to keep up with. Some say nutrition guidelines have lost their credibility because they keep changing.
But I encourage readers not to lose heart!
Nutrition Science is a learning, growing, adaptive field. Research is always building on what it currently knows. It also evolves with our lifestyle and environment – which are dynamic over time. New technology provides us with the ability to see different perspectives on things. When new findings come about, and there is enough evidence to tip the scale, recommendations shift.
Despite what it may look like, what we know about cholesterol hasn’t been totally turned upside down.
We’ve just progressed.
As far back as the 19th century scientists discovered that plaque in clogged arteries was partly made up of cholesterol. The logical connection at the time was that eating a high cholesterol diet causes clogged arteries. (2)
In the 1940’s when heart disease began rising in the U.S., research on heart disease found links between high cholesterol diets and the disease. (2)
Now we know that cholesterol doesn’t just “free float” in the blood, but rather it is “packaged” in to something called a lipoprotein. Lipoproteins are made up of cholesterol, phospholipids (fats), triglycerides (fats), and proteins.(3) The lipoprotein packages have different compositions and different sizes.
We have found that high levels of LDL, the smallest of the four LDL’s containing the highest percentage of cholesterol within the total lipids, can be most dangerous because they can essentially bang into, damage, and deposit their contents into artery walls.
The damage attracts monocytes (white blood cells) which, in trying to repair the vessel wall will create plaque. As the plaque builds, it can block the inside of the blood vessel causing atherosclerosis, and a high risk of heart disease and stroke. For this reason LDL’s are frequently called “bad” cholesterol (4,5,6,8,9).
We also found that HDL (the smallest particle) can remove fat and cholesterol from the artery walls, which is why they are often called good cholesterol or healthy cholesterol.
By the way, cholesterol is a necessary part of life. Our bodies use it to produce hormones, Vitamin D and bile salts which help us to digest fat (10). It’s an essential constituent of myelin, which is the electrically insulating sheath that covers nerve and brain cells.
We’ve since discovered that the body’s own cholesterol processing is much more influential than diet,
because the body creates it’s own cholesterol and also regulates the amount of cholesterol in it’s blood.
We all process cholesterol differently, and there are some (about 25%) whose bodies don’t regulate enough to keep the blood levels at what is currently considered to be safe due to genetics (2).
Safe levels of LDL are considered less than 130 if you have no other risk factors (12).
If you have elevated cholesterol levels, your doctor will advise you to change your diet, start to exercise, stop smoking and lose some weight to lower your LDLs (4,5,6,7). If that doesn’t work then cholesterol lowering drugs will be prescribed.
The new view on dietary cholesterol doesn’t change our view on high levels of LDL
or, the “bad” cholesterol in the blood which has been linked to heart disease. (1,2,4,5,7)
Experts still agree that diets high in saturated and trans fats are strongly associated with higher LDL cholesterol (1,4,5,7). Other lifestyle risk factors include being overweight, and lack of exercise.
There is emerging evidence
that high simple carbohydrate intake can also cause an increase the levels of LDL in the blood due to the way the liver metabolizes under the conditions of sedentary lifestyle and obesity (8, 9). There is quite a bit of difference in lifestyle and obesity compared to the 60’s, hence the guidelines may soon be updated to reflect that.
No matter what our health profile is, when we eat fat and cholesterol, our blood cholesterol levels rise.
our blood cholesterol levels go up until our body clears them. If our body is good at regulating cholesterol, our blood levels will go back to normal in a few hours. But, this is a dangerous time frame for those with heart disease and diabetes. For this reason, experts will still warn people with particular health problems to continue to avoid cholesterol-rich diets (2,4,5,6,7).
The new guidelines aren’t giving us license to go whole-hog crazy on butter, cheese and cream.
But, eating lean proteins that contain cholesterol like lobster, shrimp and eggs are considered safer to eat (and go light on the butter, cream and cheese on top… get it?).
The best way to interpret the new cholesterol information is to
- Keep focusing on eating a large variety of fruits and vegetables, which have an abundance of phytochemicals and fiber and lower risk of many diseases (7)
- Choose lean meats whenever possible and include beans, low-fat dairy, nuts and fish as protein sources as well (for variety and healthy fats) (7)
- Keep sweets and simple carbs to a minimum (8,9)
- Keep processed foods to a minimum (where you’ll find trans fats), and minimize saturated fats (animal fat, coconut oil, palm oil and palm kernel oil
- Make more food at home – so you know what’s in it (11)
Many of my clients have been able to get off cholesterol lowering drugs
or greatly reduce it after several months of exercise and a healthier diet. Exercise helps to raise levels of HDL which helps to clean up the arteries. It also helps to maintain the blood vessels’ ability to expand and contract, and it reduces blood pressure which is another precursor to heart disease.
In the future, through epigenetic research (study of how the environment impacts our genetic expression), we may even find that the 25% who are inclined to have high cholesterol can change their blood profile after certain, specific lifestyle changes are implemented over time.
By the way,
MindBodyBlast is starting up again this spring. It’s a fun, interactive, online course, where I help people create habits around the nutrition and exercise goals mentioned above. You can check it out here. If you’d like more individual attention in a more private setting, you may want to sign up to work with me one-on-one.
What are your thoughts on the subject?
Questions or comments? Please join the conversation in the comments section below.
- American Heart Association – http://blog.heart.org/new-federal-guidelines-may-lift-dietary-cholesterol-limits/
- Washington Post – http://www.washingtonpost.com/blogs/wonkblog/wp/2015/02/10/feds-poised-to-withdraw-longstanding-warnings-about-dietary-cholesterol/
- NIH VLDL Test- http://www.nlm.nih.gov/medlineplus/ency/article/003494.htm
- NIH High Cholesterol Levels – http://www.nlm.nih.gov/medlineplus/ency/article/000403.htm
- NIH Hardening of the Arteries – http://www.nlm.nih.gov/medlineplus/ency/article/000171.htm
Rensselaer Polytechnic Institute Molecular Biochemistry Online – https://www.rpi.edu/dept/bcbp/molbiochem/MBWeb/mb2/part1/lipoprot.htm
- American Heart Association – http://blog.heart.org/doctors-advice-on-the-latest-prevention-guidelines
- MeandMyDiabetes, Interview with Dr. Ron Krauss, MD, http://www.meandmydiabetes.com/2010/03/26/ldl-cholesterol-ron-krauss-md
- Dr. Ron Krauss, presentation for the American Society of Nutrition, Dec 2013.
- Web MD – http://www.webmd.com/cholesterol-management/guide/cholesterol-basics
- American Heart Association Journal – http://circ.ahajournals.org/content/114/1/82.full.pdf
- Lab Tests Online – http://labtestsonline.org/understanding/analytes/ldl/tab/test