WIDLIMS ep #16 – The skinny on cholesterol and diet
Listen to this episode and read the short article below to get the skinny on cholesterol and how to lower it, featuring host and final year medical student Linda (she/her). PLEASE NOTE this is a podcast episode and article for educational purposes only and should not be taken as individual medical advice. Listen to learn about...
- what cholesterol is
- what foods increase “bad” cholesterol levels
- what foods reduce “bad” cholesterol levels
- and some extra points regarding fish, triglycerides and apolipoprotein!
I promise it is all in accessible language, with non-medical jargon.
Consider this an overview of the topic. I would encourage further reading around this by credible organisations such as the Physician’s Committee for Responsible Medicine (PCRM), American College of Lifestyle Medicine (ACLM) or Plant-Based Health Professionals UK (PBHP-UK) which genuinely have got people’s best and education at heart, and are not relying on funding and interference from the food industry, or even the government’s health schemes in the same way that national health services of various countries may be.
Mentioned in this episode
- Physician’s Committee for Responsible Medicine. Lowering cholesterol with a plant-based diet. The perfect summary of the topic (second only to my article below…) with links to research as well as some recipe ideas. Access it here.
- Statins vs. diet: diet as efficient as statin therapy? research paper by Dr Rosenthal here, article with further reading about statins by Dr Greger here
- Previous episodes
- Getting enough plant protein: read the section on protein HERE or the more accessible page by PCRM HERE which I really like
- 2019 RCT Bergeron et al. “white” meat not better HERE
Cholesterol basics
Cholesterol is a molecule that is essential for our health, but also can cause danger if present in the wrong quantity, form or locations in the body. It is a structural component of cell membranes, and is also key in the synthesis of hormones. There are two potential ways for our body to get cholesterol: through diet, or by us making it ourselves in the liver. And the great thing is that we do not even need (or want) to obtain cholesterol through our diet, as all the cholesterol we need can be synthesised in-house! In the blood-stream, cholesterol exists in two forms depending on what protein carries it: LDL and HDL, which stands for low and high density lipoprotein respectively. Typically, LDL is termed the “bad” type of cholesterol and HDL the “good” kind. (1)
High levels of LDL cholesterol can lead to atherosclerosis, the formation of plaques in the blood vessels, which impairs blood flow and can lead to lots of unwanted consequences such as heart attacks and strokes, whereas higher HDL cholesterol means that more cholesterol is being taken from the blood stream back to the liver for processing (2,3).
What in our diets can cause an unfavourable cholesterol profile?
- lipid category: trans fats, saturated fats, cholesterol (from more to less important)
- protein category: meat
- carbohydrate category: refined carbohydrates and simple sugars
Trans fats, saturated fats and dietary cholesterol
Interestingly, dietary cholesterol does not raise total or LDL cholesterol levels as much as trans and saturated fat! (4,5,6)
However, it is not a good idea to consume cholesterol-rich foods such as eggs anyway, as dietary cholesterol can impact our total cholesterol anyway. Most foods that are high in cholesterol will also be high in saturated fat (4-7). As always, we must ask ourselves the question: what are we comparing a food to? Eggs are better than a donut in terms of health, but are they more healthful than a cup of beans? Not really. I will not go more into the topic of eggs just now, but you can read more about it at this link.
Meat
Animals make their own cholesterol, so eating the flesh of another animal means we will consume their cholesterol, whereas there is no cholesterol as we know it found in plants. Meat also has high saturated fat levels. Even eating “lean” meat is not much better, and the best thing to do for health is to not eat any meat and consume plant-based sources of protein instead (6,8).
One recent RCT published in July 2019 (9) compared the effects of “red” and “leaner” meat on heart disease markers, and found the following:
The findings are in keeping with recommendations promoting diets with a high proportion of plant-based food but, based on lipid and lipoprotein effects, do not provide evidence for choosing white over red meat for reducing CVD risk.
Bergeron et al. Paper here.
Sugar
We will talk about what types of carbohydrate-rich foods are beneficial when trying to lower cholesterol, or prevent raising cholesterol eventually. Simple sugars, such as refined carbohydrates and products with added sugar (as opposed to carbohyrate-rich foods in their unprocessed form, as found in nature and minimally prepared) can however increase total cholesterol and triglycerides in the blood (10-12).
Again, remember that fruit is not to be avoided for health, nor are whole starchy carbohydrates, legumes and whole grains. Please check out the episode on carbohydrates and insulin resistance if you are a bit unsure about this, and read the show notes. CLICK HERE!
How do we lower the “bad” cholesterol?
I will touch on lifestyle interventions, which should be first-line. Of course, there is medication such as the well-known statin drugs, that almost every other patient I encounter is on. These are not without side-effects, and if possible lifestyle interventions should either be attempted first, or continued alongside taking these drugs for maximum benefit and minimal harm to health. As always, I just think that any decision should be fully informed.
Please remember that risk reduction is not the same as absolute prevention. However, lifestyle habits can either optimise your chances of a healthy longer life, or be detrimental. Also note that for some, it might be enough to implement a few of these changes loosely, and others may need to very strictly follow a low-fat diet such as mentioned by Drs Bajekal and Kassam in previous episodes – Dr Bajekal – Dr Kassam.
Non-diet interventions
Let us not forget or underestimate the impact that all lifestyle factors have on our health and wellbeing! Things you can do to reduce your LDL cholesterol, and increase HDL cholesterol, with lots of positive side effects include quitting smoking, not drinking alcohol, exercising, and lowering stress levels (13).
Dietary interventions
We mentioned the main culprits above, and if you read between the lines you will find that all signs point toward a focus on an anti-inflammatory diet low in fat, and high in fibre. We should aim to avoid trans fats, saturated fats, and foods high in cholesterol (which are generally those high in saturated fat anyway as mentioned earlier) (14).
We should replace saturated fats with mono- and polyunsaturated fats such as those found in plants, for example in avocados, nuts and seeds (15,16). However, we do not need much in our diet so you do not need to be concerned about getting “enough”. There is no need to drizzle lots of extra olive oil over salads, just because you feel you need to meet a certain requirement! Many oils are very calorie dense, and are not to be used liberally all the time. I personally do not really use oils in cooking, but will eat dishes made with oil when I am eating out or so.
Please note that not all plant sources of fat are healthful: palm and coconut oil are best avoided for health purposes, as they also contain a lot of saturated fat. Of course, having it occasionally should be fine unless you have severe heart disease and want to reverse it with dietary interventions only. The saturated fat found in cocoa and dark chocolate may however be beneficial to cholesterol profiles… yum! (17)
We also know that fibre is amazing for reducing unwanted cholesterol (18,19)! And only plant foods have fibre: find it in vegetables, fruit, whole grain and legumes for example. I am pleased to say that guidelines with recommendations for heart health such as those of the NHS and BHF promote a high fibre content in our diets.
Particularly beneficial foods include (14):
- foods high in soluble fibre such as oats, beans, barley
- soya products
- nuts
- foods high in phytosterols, aka plant sterols: Brussels sprouts, wheat germ, almonds
As well as choosing certain foods over others, remember to use alternative ways of cooking. You may want to fry foods less and avoid excessive oil use, and opt for baking, boiling or steaming instead. AGEs are not healthy for the cardiovascular system either! More on AGEs in the show notes here.
A note about fish
Many guidelines – sadly the very same ones that recommend an increased fibre intake – also recommend consuming oily fish as a source of omega-3 fatty acids. In an otherwise healthy diet – and by that I mean a largely whole food plant-based diet – it is unlikely to do much harm, but we must always ask ourselves what is the food being replaced with? If you are having fish instead of some fiber-rich legumes, it is perhaps not so wise or helpful. If you are having a fillet of fish instead of deep-fried fish and chips, it might be better – but it could be better still! Fish is not essential in our diet, as we can get omega-3 from foods such as ground flaxseeds, hemp seeds, ground chia seeds and walnuts. Be sure to consume an adequate amount daily (~1 tablespoon), and consider taking an algae-based supplement (20).
And what about other markers of heart disease?
Apolipoprotein
Recent research indicates that purely using LDL or HDL cholesterol as markers might not be enough. In an individual with high LDL cholesterol it might be useful to know how many particles there are in the blood, and whether there are many small LDL particles or fewer larger LDL particles. Apolipoprotein B can be used as a proxy marker for this, as each LDL component will contain one of those, but is not regularly measured in clinical practice at this point in time (21,22).
Triglycerides
Having higher triglycerides has also been associated with higher risks of heart disease, but most people who have high triglycerides will be consuming more saturated fats, and foods in general that increase LDL cholesterol levels, too (1,23). So the approach for such persons would be the same as mentioned above.
Low HDL or high LDL?
Remember that cholesterol is a marker for cardiovascular disease, a proxy we use. It is all about risk reduction, but we must not rely on the numbers only. Some people will have higher cholesterol levels even after implementing all these changes – and if they have strictly followed every recommendation and using diet and lifestyle as therapeutic tools, they may have familial hypercholesterolaemia.
One study showed that some individuals following a low fat WFPB diet had lower HDL cholesterol in addition to other biomarkers that predict lower heart disease risk. Using HDL cholesterol as a marker might therefore not be warranted in such populations which clearly are at lower risks of heart disease (24).
Low HDL is associated with many other poor health outcomes and health behaviours, but if these are not an issue, such as in an otherwise healthy individual, there is less cause for concern (25).
Bringing it all back together…
In summary, remember that lifestyle factors can be incredibly powerful as therapeutic tools and in disease prevention (more accurately: risk reduction). If a patient has a longstanding problem, it may be necessary to very strictly follow a low-fat whole food plant-based diet. For the rest, it might not need to be as strict as that.
Please also remember to take dietary guidelines with a grain of salt. Especially if they recommend “some” meat, or “some” dairy product, such as the British Heart Foundation does… Focus on fibre! And remember all the other things such as exercise, smoking cessation and keeping healthy in other aspects of our lives.
REFERENCES
1) https://www.hopkinsmedicine.org/health/conditions-and-diseases/high-cholesterol/cholesterol-in-the-blood
2) https://www.cdc.gov/cholesterol/ldl_hdl.htm
3) http://www.bloodpressureuk.org/your-blood-pressure/how-to-lower-your-blood-pressure/healthy-eating/fats-and-cholesterol-and-your-blood-pressure/?gclid=CjwKCAjwiaX8BRBZEiwAQQxGx-5h_ukmxraqEvvhW0DlaUD07i-0uyjy7Z9Liee-ZgPHzXHgR5xDuBoCkLwQAvD_BwE
4) Soliman GA. Dietary Cholesterol and the Lack of Evidence in Cardiovascular Disease. Nutrients. 2018;10(6):780. Published 2018 Jun 16. doi:10.3390/nu10060780 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6024687/
5) https://www.pcrm.org/news/health-nutrition/dietary-cholesterol-increases-bad-cholesterol-levels
6) Praagman J, Vissers LET, Mulligan AA, et al. Consumption of individual saturated fatty acids and the risk of myocardial infarction in a UK and a Danish cohort. Int J Cardiol. 2019;279:18-26. doi:10.1016/j.ijcard.2018.10.064 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6774776/
Hello, if you are down here checking out the references! I made a mistake so there are two number 6, but I didn’t want to shift the entire thing. I hope it still makes sense 🙂
6) https://www.pcrm.org/news/blog/cholesterol-confusion-lets-make-sense-it
7) Zhu Z, Wu F, Lu Y, et al. The Association of Dietary Cholesterol and Fatty Acids with Dyslipidemia in Chinese Metropolitan Men and Women. Nutrients. 2018;10(8):961. Published 2018 Jul 25. doi:10.3390/nu10080961 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6115945/
8) https://www.health.harvard.edu/blog/when-it-comes-to-cholesterol-levels-white-meat-may-be-no-better-than-red-meat-and-plant-based-protein-beats-both-2019082217550
9) Nathalie Bergeron, Sally Chiu, Paul T Williams, Sarah M King, Ronald M Krauss, Effects of red meat, white meat, and nonmeat protein sources on atherogenic lipoprotein measures in the context of low compared with high saturated fat intake: a randomized controlled trial, The American Journal of Clinical Nutrition, Volume 110, Issue 1, July 2019, Pages 24–33, https://doi.org/10.1093/ajcn/nqz035
10) DiNicolantonio JJ, Lucan SC, O’Keefe JH. The Evidence for Saturated Fat and for Sugar Related to Coronary Heart Disease. Prog Cardiovasc Dis. 2016;58(5):464-472. doi:10.1016/j.pcad.2015.11.006 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4856550/#R49
11) Te Morenga LA, Howatson AJ, Jones RM, Mann J. Dietary sugars and cardiometabolic risk: systematic review and meta-analyses of randomized controlled trials of the effects on blood pressure and lipids. Am J Clin Nutr. 2014 Jul;100(1):65-79. doi: 10.3945/ajcn.113.081521. Epub 2014 May 7. PMID: 24808490. https://academic.oup.com/ajcn/article/100/1/65/4576668
12) Welsh JA, Sharma A, Abramson JL, Vaccarino V, Gillespie C, Vos MB. Caloric Sweetener Consumption and Dyslipidemia Among US Adults. JAMA. 2010;303(15):1490–1497. doi:10.1001/jama.2010.449
13) https://www.health.harvard.edu/newsletter_article/elevating-your-hdl-game
14) PCRM. Lowering cholesterol with a plant-based diet. https://www.pcrm.org/good-nutrition/nutrition-information/lowering-cholesterol-with-a-plant-based-diet
15) https://www.hsph.harvard.edu/nutritionsource/what-should-you-eat/fats-and-cholesterol/
16) https://www.hsph.harvard.edu/nutritionsource/what-should-you-eat/fats-and-cholesterol/types-of-fat/
17) Baba S, Natsume M, Yasuda A, Nakamura Y, Tamura T, Osakabe N, Kanegae M, Kondo K. Plasma LDL and HDL cholesterol and oxidized LDL concentrations are altered in normo- and hypercholesterolemic humans after intake of different levels of cocoa powder. J Nutr. 2007 Jun;137(6):1436-41. doi:10.1093/jn/137.6.1436. PMID: 17513403.
18) NutritionFacts.org. How fiber lowers cholesterol https://nutritionfacts.org/video/how-fiber-lowers-cholesterol/
19) Reynolds A, Mann J, Cummings J, Winter N, Mete E, Te Morenga L. Carbohydrate quality and human health: a series of systematic reviews and meta-analyses. Lancet. 2019 Feb 2;393(10170):434-445. doi: 10.1016/S0140-6736(18)31809-9. Epub 2019 Jan 10. Erratum in: Lancet. 2019 Feb 2;393(10170):406. https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(18)31809-9/fulltext
20) https://www.pcrm.org/news/blog/get-omega-3s-plants-not-fish-oil
21) Pencina MJ, D’Agostino RB, Zdrojewski T, et al. Apolipoprotein B improves risk assessment of future coronary heart disease in the Framingham Heart Study beyond LDL-C and non-HDL-C. European Journal of Preventive Cardiology. 2015;22(10):1321-1327. doi:10.1177/2047487315569411
22) https://www.sciencemag.org/news/2017/12/it-time-retire-cholesterol-tests
23) Nordestgaard BG, Varbo A. Triglycerides and cardiovascular disease. Lancet. 2014 Aug 16;384(9943):626-635. doi: 10.1016/S0140-6736(14)61177-6. PMID: 25131982. https://linkinghub.elsevier.com/retrieve/pii/S0140-6736(14)61177-6
24) Kent L, Morton D, Rankin P, et al. The effect of a low-fat, plant-based lifestyle intervention (CHIP) on serum HDL levels and the implications for metabolic syndrome status – a cohort study. Nutr Metab (Lond). 2013;10(1):58. Published 2013 Oct 1. doi:10.1186/1743-7075-10-58 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3849684/
25) https://www.health.harvard.edu/blog/low-levels-of-hdl-the-good-cholesterol-appear-connected-to-many-health-risks-not-just-heart-disease-2016110210626
Healthy eating according to the BHF: https://www.bhf.org.uk/informationsupport/support/healthy-living/healthy-eating
Healthy eating according to the NHS: https://www.nhs.uk/live-well/healthy-body/lower-your-cholesterol/
