Cholesterol

Cholesterol

TL:DR

  • Blood cholesterol is needed for your body to function
  • Dietary cholesterol, for most people, has no significant impact on your cholesterol numbers
  • HDL = good
  • LDL and triglycerides = bad
  • Diet low in saturated fat, high in fiber and omega-3 = beneficial
  • Exercise and Weight loss [If you’re overfat or overweight] = good

Definitions

Blood cholesterol

  • Main building blocks used to make cell membranes
  • Essential for the synthesis of vitamins and hormones

Two forms

  • Free or Unesterified Cholesterol (UC)
  • Active or Esterified/Storage form Cholesterol (CE – Cholesterol Ester)
    • 50% of dietary cholesterol
    • Cannot be absorbed

There is another nuance to this, which is where the CE versus UC distinction comes in:

Only free or unesterified cholesterol (UC) can be absorbed through gut enterocytes. In other words, cholesterol esters (CE) cannot be absorbed because of the bulky side chains they carry. Much (> 50%) of the cholesterol we ingest from food is esterified (CE), hence we don’t actually absorb much, if any, exogenous cholesterol (i.e., cholesterol in food). CE can be de-esterified by pancreatic lipases and esterolases – enzymes that break off the side branches and render CE back to UC — so some ingested CE can be converted to UC.

Source: http://eatingacademy.com/nutrition/the-straight-dope-on-cholesterol-part-i

We ingest and produce cholesterol (primarily by the liver) – 25% dietary intake 75% body

  • Most of cholesterol is made by our own body
  • If dietary cholesterol drops, body production increases

The panel also dropped a longstanding recommendation that Americans restrict their intake of dietary cholesterol from foods like eggs and shrimp — a belated acknowledgment of decades of research showing that dietary cholesterol has little or no effect on the blood cholesterol levels of most people.

“For many years, the cholesterol recommendation has been carried forward, but the data just doesn’t support it,” said Alice H. Lichtenstein, the vice chairwoman of the advisory panel and a professor of nutrition science and policy at Tufts University.

Source: http://mobile.nytimes.com/blogs/well/2015/02/19/nutrition-panel-calls-for-less-sugar-and-eases-cholesterol-and-fat-restrictions/

Lipoproteins

Required for the transportation and metabolism of lipids in the body

High-density Lipoprotein Cholesterol (HDL)

  • Brings extra cholesterol from the blood to the liver for disposal
  • “Good” cholesterol.

Low-density lipoprotein cholesterol (LDL)

  • Ferries cholesterol to areas which needs it for cell repair and also deposits it on inside of artery walls
  • “Bad” cholesterol

Very low-density Lipoprotein Cholesterol (VLDL)

  • High number is correlated with higher CVD risk

Source: https://www.ncbi.nlm.nih.gov/pubmedhealth/PMHT0022289/

When/where is cholesterol bad?

  • Inside artery walls especially coronary artery and carotid artery
  • Leads to inflammation which results in the blockage of arteries

 Infographic for the lazy

Triglycerides

  • Main type of fat transported by your body
  • Liver also produces triglycerides and changes some into cholesterol
  • High consumption of carbohydrates, especially simple sugars, have been correlated with high levels of triglycerides
  • High levels are associated with coronary heart disease, diabetes and fatty liver disease

Improving cholesterol numbers

Weight loss

Even a modest reduction in weight (5-10%) has been correlated with significant improvements in triglycerides, total cholesterol and LDL numbers. In fact, the larger the extent of the weight loss (>10%), the greater the effect.  In addition, weight reduction has shown to help prevent T2 diabetes and reduce levels of inflammation markers.

Essential Fatty Acids (EFA) supplementation

Diets high in omega-3 content have been correlated with improved cholesterol numbers. Although there is no strong evidence of it’s effect on HDL and LDL numbers, it has shown to have a dose-dependent effect on triglyceride reduction.

Besides potentially improving cholesterol numbers, omega-3 supplementation as low as 180mg EPA and 120 DHA has  been correlated with decreased body weight, blood pressure and circulating levels of inflammation markers such as CRP and HSP27

capture

Table 3 shows the recommendations given to general, healthy populations. Several authorities/organizations specify that people with documented health issues, such as CVD, may need more n-3 than the general population. For instance, AHA recommends two weekly seafood meals for people without documented CHD, 1 g EPA + DHA for people with documented CHD and 2–4 g EPA + DHA for people in need for lowering TAG
Source: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4613328/

Dietary interventions

Increase in fiber intake, especially soluble fiber ( 2-10g/d) has been associated with small but significant decreases in total cholesterol.  In fact, fiber has a whole slew of benefits. Here’s an excerpt from Lyle McDonald’s article on the benefits of fiber:

Promoting fullness/satiety

Slowing gastric emptying

Decreasing blood cholesterol

Effects on insulin sensitivity via fermentation to short-chain fatty acids

A number of effects relevant to colon cancer

Helps with poopin’

I highly recommend reading the full article for the complete details.

In addition to increasing fiber, eating a diet that is low in saturated fats by replacing saturated fats with unsaturated fats as much as possible rather than a low-fat diet seems to be more effective in helping with cholesterol and CVD. Sources of MUFA and PUFA include: walnuts, olive oil, sunflower oil, peanuts, almonds and hazelnuts.

Exercise

Exercise or physical activity in general has shown to help with not only improving cholesterol numbers but also help with blood pressure, depression, dementia and hyperlipidemia. Check out this massive review for evidence for prescribing exercise as therapy in 26 different chronic diseases

Effect of 14 weeks of resistance training on lipid profile and body fat percentage in premenopausal women

RESULTS: Two way analysis of variance with repeated measures showed significant (p < 0.05) increases in strength (1-RM) in the exercising group. There were significant (p < 0.05) decreases in total cholesterol (mean (SE) 4.68 (0.31) v 4.26 (0.23) mmol/1 (180 (12) v 164 (9) mg/dl)), low density lipoprotein (LDL) cholesterol (2.99 (0.29) v 2.57 (0.21) mmol/l (115 (11) v 99 (8) mg/dl), the total to high density lipoprotein (HDL) cholesterol ratio (4.2 (0.42) v 3.6 (0.42)), and body fat percentage (27.9 (2.09) v 26.5 (2.15)), as well as a strong trend towards a significant decrease in the LDL to HDL cholesterol ratio (p = 0.057) in the resistance exercise training group compared with their baseline values.

When it comes to the good cholesterol, fitness trumps weight:

The study authors found that HDL functioned better in the participants who had a regular weight-lifting program, regardless of their weight—overweight exercisers’ HDL has similar effectiveness as an antioxidant as the lean exercisers’ HDL cholesterol. Both groups’ HDL performed significantly better than those who didn’t exercise. Such dysfunctional HDL was associated with numerous other factors associated with heart disease, such as elevated triglycerides and trunk fat mass.

Importance of the Findings
These findings suggest that regular weight training might improve HDL function and protect against heart disease, even in those who remain overweight. Although indices of weight were associated with HDL cholesterol function, differences in fitness, the authors say, may be a better measure of who has healthier functioning HDL cholesterol, and therefore, who is at risk of heart disease.

 

 

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s