Q: I am a healthy weight and recently changed my diet to a vegan diet. Since then, my doctor has told me that my triglycerides are high: they are 215. Why are they high? What can I do, and is it important for me to improve these numbers?
A: When you go to a doctor and get your fasting cholesterol test results, it can be an exercise in confusion. You will get numbers for your total cholesterol, LDL cholesterol (or ‘unhealthy’ cholesterol), HDL cholesterol (or ‘healthy’ cholesterol), and triglycerides. Currently, the major emphasis in treating abnormal cholesterol results is in getting LDL cholesterol below a certain goal level; but you may also get advice to keep your HDL high and your triglycerides low. If your fasting triglycerides are above 150, but below 500, it probably is not uncommon to leave the doctor’s office with more questions than answers, as this can be a gray zone.
Why do we care about triglycerides? Triglycerides matter because they are a harbinger of cardiovascular disease.[1] While people with higher triglycerides have a higher risk of cardiovascular disease, it can be tricky to know whether the triglycerides themselves are the true cause of the increased risk. This is because high triglycerides often occur in conjunction with a host of other abnormalities, including high blood sugar, low HDL (‘healthy’) cholesterol, obesity, diabetes, and high blood pressure[1]. In addition, specific types of cholesterols and fats in the blood stream are likely to be different in qualitative ways. LDL particles (the ‘unhealthy’ cholesterol) are likely to be smaller and denser[2], which is even more dangerous than normal LDL particles. As you can tell, the links between different cholesterol and fat fractions get complicated quickly, and it becomes difficult to disentangle which factor causes what. The one thing we can agree on is that high triglycerides are linked to increased risk of cardiovascular disease.
There is a significant range of triglyceride results. Most consensus panels have created a categorization similar to the following breakdown:
| Triglyceride Classification | Triglyceride Levels |
|---|---|
| Normal | Below 150 |
| Borderline | 150 to 200 |
| High | 200 to 500 |
| Very High | 500 to 1000 |
| Severe | Above 1000 |
High triglycerides can be caused by a variety of non-lifestyle related factors: (1) inherited genetic problems, including familial combined hyperlipidemia, familial hypoalphalipoproteinemia, and monogenic familial hypertriglyceridemia (I know – they’re a mouthful), each of which affect about 1% of the population[2], (2) thyroid problems, (3) serious kidney disease, (4) pregnancy, and (5) medications. Medications are listed in Table 2.
| Medications |
|---|
| Estrogens (oral contraceptives)[3] |
| Some types of blood pressure lowering medications (thiazide diuretics and beta-blockers) |
| Glucocorticoids (steroids like prednisone) |
| Androgens (testosterone) |
| Acne medicines (isotretinoin) |
| Immune System Medications (cyclosporine, tacrolimus) |
In terms of lifestyle, diet, drink, and exercise all play a role in triglyceride levels. One recent review[4] states that those people eating plant-based diets, over the long term, consistently have lower triglyceride levels, but interventional trials have been less consistent. Randomized control trials show that triglycerides may either increase or decrease when switching to a plant-based diet; most trials reviewed show that triglycerides either go up or down by less than roughly 25 in either direction[4]. In addition, excessive alcohol intake, as well as a sedentary lifestyle[5], can raise triglycerides.
So what do we do about a high triglyceride level? When it comes to medications the recommendations can be a bit fuzzy. There is no great evidence that driving down mild to moderate triglyceride levels, with medications specifically targeted at triglyceride levels, significantly improves cardiovascular disease risks[6]. In the context of relatively normal cholesterol results, the standard treatment of borderline to mild hypertriglyceridemia is lifestyle changes, if there is no other obvious cause (medications, etc…). As an aside, those people with very high or severe range triglycerides may be at increased risk of pancreatitis, and prescribing medication to specifically lower triglycerides in this case is often indicated.
Lifestyle changes can make a significant impact in lowering triglycerides. Moderate to high intensity aerobic exercise can lower triglycerides by up to 10-20%[5]. Reduced alcohol intake may improve triglycerides as well, especially if there is an issue with excessive intake or individual predisposition to high triglycerides[5]. In terms of diet, the standard recommendation for mildly elevated triglycerides is to reduce refined carbohydrate intake, particularly sugars. Fruit juice, refined flour, sweets, and any plant that has the fiber removed should be off limits. Another way to consider this is to try to eat low-glycemic index foods (foods that don’t raise blood sugar as high or quickly as other foods)[6][7]; but solely focusing on glycemic index has not always been shown to make a significant difference in triglycerides[8]. Those with very high triglycerides should also monitor all fat intake and be very careful not to consume any added fat[6]. A frequently asked related question involves whether people should be boosting omega-3 fats, commonly associated with fish consumption. The short answer is that I do not recommend fish oil or omega-3 supplements for mild to moderately high triglycerides.
In summary, despite the long explanation, the recommendations remain the same: limit or reduce alcohol use, incorporate exercise regularly, consume a high-fiber, whole-food, plant-based diet without added fats, and avoid white flours, added sugars, and juices. Good luck!
A special thank you to Tomi, who posed this question to us on the T. Colin Campbell Center for Nutrition Studies Facebook page.
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