Diaries of a Plant Powered Dietitian

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Butter or Bust

I know, I know. I realize this is a plant-based eating blog but I couldn’t resist backing up butter here. Before the vegans come running at me with pitchforks and my fellow dietitian readers gasp in dismay that I tell my clients to use butter instead of margarine, hear me out. Although saturated fat has been vilified since the U.S. Dietary Guidelines were first published in 1980 and Americans were told to lay off the butter and eggs, we have very strong research to indicate saturated fat may not be as “bad” as we think. However, the current guidelines still recommend limiting saturated fat intake to less than 10% of total daily calories and replacing it with a group of long chain unsaturated fats known as polyunsaturated fatty acids, specifically encouraging the use of soybean, corn, safflower oil and margarines.

I have three concerns with these recommendations:

1) the recommendation to swap saturated fats with polyunsaturated oils (long chains of unsaturated fatty acids) is not a well-tested guideline, and the strong data we do have indicates this may actually increase risk of heart disease due to the pro-inflammatory nature of some of these oils

2) saturated fats have been lumped into one category, while there are many different types of saturated fats and some have neutral, if not beneficial effects on health

3) swapping saturated fats means that we are replacing calories and nutrients with something else, which is usually sugar and processed vegetable oils riddled with omega-6 fats that may cause more harm than good

Here’s a little refresher on foods high in saturated fat:

  • Regular dairy products (not non-fat)
  • Gravies
  • Eggs
  • Processed meats, red meat, and pork
  • Grain-based desserts (think donuts, cookies, pastries, croissants, etc.)
  • Packaged snack and convenience foods (TV dinners, boxed/frozen meals, chips, crackers)
  • Mixed dishes that contain high amounts of cheese and meat like burgers, sandwiches, and pizza
  • Deep-fried foods
  • Some fats like butter, lard, and  tropical oils like coconut and palm oil

But first, a little history:

The phenomenon surrounding the message to lower saturated fat intake has been referred to as the “diet heart hypothesis” which stemmed from series of ongoing population studies that began in the 1950s and found that folks in Mediterranean and Asian countries who at more olive oil, fish, legumes, and fruits and vegetables (low saturated fat diets) lived longer and had lower risk of heart disease than those in northern Europe who ate more meat and dairy (higher saturated fat diets). This was a correlation, not a cause and effect. Researchers supporting this hypothesis believe that replacing saturated fat specifically with linoleic acid (a type of omega-6 unsaturated fatty acid) lowers heart disease risk by reducing total blood cholesterol levels and slowing the progression of clogged arteries, but in reality these guidelines were never actually tested with clinical trials prior to their introduction. The randomized clinical trial is the “gold standard” of research, meaning a scientific hypothesis is tested in a controlled environment that makes every effect to eliminate variables, therefore being able to draw conclusions from the data, or a direct cause and effect. It is concerning that the dietary guidelines were based off only secondary prevention studies, and are to this day (1).

Saturated fat and heart health:

In my opinion, the role that saturated fats play in heart health has been oversimplified by the governing bodies that dictate health recommendations. We now know total cholesterol in the blood has negligible meaning for heart health and that it’s more about the ratio of LDL (bad) cholesterol to HDL (good) cholesterol in the blood. We want our HDL levels to be high because they dispose of the more harmful LDL cholesterol particles. We actually have research to show that lowering LDL cholesterol without also raising HDL cholesterol isn’t necessarily beneficial, and can even be harmful (2,3). One of the best ways to boost our HDL cholesterol levels is to eat more saturated fat.

We now have abundant research to show that saturated fats have no effect on heart disease or mortality risk. Recent meta-analyses (major studies that pull data from many trials) have found no link between saturated fat, heart disease, type 2 diabetes, and overall mortality (4-7).

Another important consideration is what nutrient is replacing our saturated fat intake if we lower it. When saturated fat intake replaces refined carbohydrates (sugar), this lowers triglyceride levels (a good thing), and despite raising LDL cholesterol, it also raises HDL cholesterol and thus improves the total to HDL cholesterol ratio. (8). The vast majority of research points to refined carbohydrates and the industrial (man-made) trans fats that are found in margarines and processed foods as much more detrimental to our health than saturated fat (9,10). Interestingly, although saturated fat does raise our LDL cholesterol, high saturated fat diets tend to change the composition of the LDL particles to make them less likely to stick to the arteries and thus less harmful.

Plus, there are several different types of saturated fats and they affect heart health differently. For example, lauric acid (found in coconut and palm kernel oil) is a potent raiser of our good cholesterol, and can even promote weight loss and reduction of abdominal fat. Stearic acid, which is found in lard, beef, and cocoa butter, has neutral effects on cholesterol levels.

It is also worth mentioning that dietary intake of saturated fat does not necessarily translate to high levels of saturated fat in the bloodstream. In fact, the more detrimental “even chain” saturated fats floating around in the bloodstream are mostly influenced by dietary intake of sugar, starch, alcohol, and, interestingly enough, margarine, and not by dietary intake of high saturated fat foods (11-13). All in all, it appears that dietary saturated fat does not affect blood levels of saturated fat as much as refined carbohydrate does (14-15).

Conclusions:

I am not promoting that we suddenly start eating gobs of animal fat (which has its own environmental implications), but moderate amounts of saturated fat can be healthy and appropriate, especially if consumed in place of refined carbohydrates and trans fats. Americans actually get most of their saturated fat intake from mixed dishes like pizza, burgers, and sandwiches, followed by grain-based desserts and sweets (NHANES, 2010). These foods are high in sodium and sugar, and are loaded with refined grains, cheese, and processed meats, which we shouldn’t be eating a lot of anyways. The issue is that we often eat too much sugar and processed foods along with, or part of, our saturated fat intake.

Although natural plant oils rich in monounsaturated fats and omega-3 fats like olive oil, avocado, and flaxseed oils are my go-to’s most of the time, I am not on team margarine due to its high omega-6 fatty acid content from soybean and corn oils, and its inclusion of palm oil (which continues to be an ongoing environmental and human trafficking problem in Southeast Asia). I suggest skipping the processed vegetable oil spreads and opting for natural, unadulterated saturated fats, which are perfectly acceptable to include as part of a well-rounded diet as long as they fit within daily calorie needs. I recommend:

  • Unrefined coconut oil
  • Butter from grass-fed cows
  • Ghee
  • Pasture raised unprocessed meats, milk, and yogurt (for you meat eaters out there)

Disclaimer: The thoughts in this blog post are solely mine and do not reflect the views of any major health organizations. The information contained is not meant to constitute medical advice.

References:

1.       Harcombe Z, Baker JS, Cooper SM, et al. Evidence from randomized controlled trials did not support the introduction of dietary fat guidelines in 1977 and 1983: a systematic review and meta-analysis. Open Heart 2015. doi:10.1136. https://openheart.bmj.com/content/2/1/e000196

2.       Ramsden CE, Zamora D, Leelarthaepin B, et al. Use of dietary linoleic acid for secondary prevention of coronary heart disease and death: evaluation of recovered data from the Sydney Diet Heart Study and updated meta-analysis. BMJ 2013;346:e8707. https://www.bmj.com/content/bmj/346/bmj.e8707.full.pdf

3.       Frantz ID Jr, Dawson EA, Ashman PL, et al. Test of effect of lipid lowering by diet on cardiovascular risk. The Minnesota Coronary Survey. Arteriosclerosis 1989;9:129–35. https://www.bmj.com/content/bmj/353/bmj.i1246.full.pdf

4.       Russell J de Souza, Mente A, et. al. Intake of Saturated and trans unsaturated fatty acids and risk of all-cause mortality, cardiovascular disease, and type 2 diabetes: A systematic review and meta-analysis of observational studies. BMJ 2015;351:h3978 doi: 10.1136/bmj.h3978. https://www.bmj.com/content/bmj/351/bmj.h3978.full.pdf

5.       Chowdhury R, Warnakula S, Kunutsor S, et al. Association of Dietary, Circulating, and Supplement Fatty Acids With Coronary Risk. A Systematic Review and Meta-analysis. Ann Intern Med. 2014;160:398-406. https://www.repository.cam.ac.uk/handle/1810/247312

6.       Siri-Tarino PW, Sun Q, Hu FB, Krauss RM. Meta-analysis of prospective cohort studies evaluating the association of saturated fat with cardiovascular disease. Am J Clin Nutr 2010;91:535-46. https://academic.oup.com/ajcn/article/91/3/535/4597110

7.       Mente A, de Koning L, Shannon HS, Anand SS. A systematic review of the evidence supporting a causal link between dietary factors and coronary heart disease. Arch Intern Med 2009;169:659-69. http://www.dcscience.net/mente-aim-2009.pdf

8.       Ronald P Mensink, Peter L Zock, Arnold DM Kester, and Martijn B Katan. Effects of dietary fatty acids and carbohydrates on the ratio of serum total to HDL cholesterol and on serum lipids and apolipoproteins: a meta-analysis of 60 controlled trials. Am J Clin Nutr 2003;77:1146–55. https://academic.oup.com/ajcn/article/77/5/1146/4689813

9.       Micha R, Mozaffarian D. Saturated fat and cardiometabolic risk factors, coronary heart disease, stroke, and diabetes: a fresh look at the evidence. Lipids 2010;45:893-905.

10.   Mensink RP, Katan MB. 1990. Effect of dietary trans fatty acids on high-density and low-density lipoprotein cholesterol levels in healthy subjects. N. Engl. J. Med. 323:439–45.

11.   Forouhi NG, Koulman A, Sharp SJ, et al. Differences in the prospective association between individual plasma phospholipid saturated fatty acids and incident type 2 diabetes: the EPIC-InterAct case-cohort study. Lancet Diabetes Endocrinol 2014;2:810-8. http://europepmc.org/articles/PMC4196248;jsessionid=5687C87F4CDAA9315DBBA4367A388863

12.   Erickson, S. et. al. Food sources of fat may clarify the earlier inconsistent role of dietary fat intake for incidence of type 2 diabetes. European Association for the Study of Diabetes 2014 Meeting; Sept 16, 2014.  Vienna, Austria. Abstract 62. https://pdfs.semanticscholar.org/eeb6/32df616fc338df88e1d74262a2affcbcb385.pdf

13.   Sluijs I, Forouhi NG, Beulens JW, et al. The amount and type of dairy product intake and incident type 2 diabetes: results from the EPIC-InterAct Study. Am J Clin Nutr 2012;96:382-90. https://academic.oup.com/ajcn/article/96/2/382/4576917

14.   Volk BM, Kunces LJ, Freidenreich DJ, Kupchak BR, Saenz C, et al. (2014) Effects of Step-Wise Increases in Dietary Carbohydrate on Circulating Saturated Fatty Acids and Palmitoleic Acid in Adults with Metabolic Syndrome. PLoS ONE 9(11): e113605. doi:10.1371/journal.pone. 0113605. http://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0113605&type=printable

15.   Hudgins LC, Hellerstein M, Seidman C, Neese R, Diakun J, Hirsch J. Human fatty acid synthesis is stimulated by a eucaloric low fat, high carbohydrate diet. J Clin Invest 1996;97:2081-91.