Many of you have Hypothyroidism and high blood cholesterol levels. Is this a coincidence? Definitely not! It is also not a coincidence that you have diabetes or PCOS along with Hypothyroidism and high cholesterol. (More on this later).In biology, coincidence is very rare. Your body is a network-of-networks. Therefore there is no condition that occurs in isolation.
What is the relationship between hypothyroidism and high cholesterol?
Good clinical medicine recommends that if you have hypothyroidism or diabetes your lipid profile must be checked. And likewise, if you have diabetes or high cholesterol, your thyroid function should be checked.
Essentially every part of your body is affected by thyroid hormones. It is no wonder that you feel unwell when your thyroid function is not optimal! You have been told that if you have high cholesterol you are at a high risk for heart disease and stroke. You may have been prescribed a cholesterol-lowering medication like atorvastatin (statins). Many of you have been asked to avoid eating eggs and coconuts and coconut oil! Before going forward, let me state here that
Cholesterol From Food Is not related to your blood cholesterol levels!Your body makes cholesterol from other sources.
What are the lipid changes associated with hypothyroidism?
The commonest changes in lipid profile are the following:
- High total cholesterol
- Low HDL-C ( “good cholesterol”)
- High LDL-C (“bad cholesterol”
- High triglycerides
The ones in the list below are not checked routinely, but the level of these may be raised/abnormal as well.
- Lp(a)
- ApoB
- ApoA-I
- Oxidized LDL-C
- Lipid particle number and size
BOTTOMLINE: All these lipid changes indicate a high risk for heart disease and stroke.
How do these changes come about?
For any blood markers to rise, either it is produced in higher amount or it is cleared less efficiently. High cholesterol with hypothyroidism occurs because of thyroid hormones affecting the following:
- Liver
- Lower lipoprotein lipase activity increasing triglyceride levels
- Increased oxidation (not good)
- The conversion of cholesterol to bile acids and excretion in faeces is an important mechanism for the removal of cholesterol from the body. Constipation (a common symptom of hypothyroidism) and poor gut health affects this pathway.
Will treating hypothyroidism normalize cholesterol levels?
This is a very important question because you would like to know whether having “normal” thyroid function tests mean that you have lowered your risk for heart disease and stroke.
Studies have shown that lipid numbers may still be abnormal even if thyroid tests are in the normal range. The subject of a paper in The Journal of Clinical Endocrinology & Metabolism (Biondi,2018) states it accurately: “Persistent Dyslipidemia in Patients With Hypothyroidism: A Good Marker for Personalized Replacement Therapy?“
Will adding T3 or T4T3 combination therapy help cholesterol abnormalities?
Whether to use T4 only or a combination of T3 and T4 or a compounded formulation depends on several factors. Most importantly, it will depend on what is available in your country and the expertise of your healthcare provider.
I have discussed T4 and T3 therapy on another post. It is important to remember that using only T4 (which is the standard recommendation) sometimes does not raise T3 levels to optimal levels. Low T3 adversely affects heart function and lipid profile. But very low TSH and/or high Free T4 is related to heart rhythm abnormalities. So it is a Goldilocks situation, neither too much nor too little!
Insulin Resistance and smoking are two major factors related to hypothyroidism and cholesterol.
If you are pre-diabetic or diabetic or insulin resistant and a smoker, your risk for heart disease, stroke, cholesterol abnormalities…..all are raised dramatically. Thyroid function , even in those with normal thyroid activity are related to insulin resistance and good vascular health ((1)) Therefore managing ALL of them rather than focussing on ONLY cholesterol is very important.
Will statin (cholesterol lowering) medications help ?
Lipid abnormalities is ONE of the many risk factors for heart disease. Therefore addressing multiple risk factors rather than focussing on only cholesterol will give you much better long term health.
Whether taking a statin medication if you have never had heart disease before (primary prevention) is right for you is a question for your doctor. Most studies do not support this.However, it is very important to keep in mind that having suboptimal thyroid function is often related to statin intolerance ((2))
Additionally, sometimes statin medications may increase your risk for diabetes.
BOTTOM LINE
- There is no one-size-fits-all solution.
- Having optimal thyroid function AND normal lipids may need a multipronged approach.
- Using only T4 to “normalize” TSH does not always translate to having normal lipids. It needs a more nuanced solution.
