Serum Lipids Explained
What your cholesterol numbers really mean — and an Ayurvedic lens on each
What Are Serum Lipids?
The word serum refers to the liquid part of your blood once all cells and clotting factors have been removed. Lipids are fatty molecules — they don't dissolve in water, so the body transports them packaged inside protein carriers called lipoproteins. A serum lipid panel measures the concentration of these fat-carrying particles in your bloodstream.
The main components measured are:
- Total Cholesterol — the combined measure of all cholesterol-carrying particles
- LDL Cholesterol (Low-Density Lipoprotein) — often called the "carrier" fraction
- HDL Cholesterol (High-Density Lipoprotein) — the protective, scavenging fraction
- Non-HDL Cholesterol — total cholesterol minus HDL; captures all potentially atherogenic particles
- Triglycerides — blood fats that reflect carbohydrate and sugar intake
- Total Cholesterol : HDL Ratio — a single number expressing the balance of risk and protection
Cholesterol itself is not a poison. It is essential to life — it is the raw material for every steroid hormone (including oestrogen, testosterone and cortisol), for vitamin D, for bile acids that digest fat, and for the integrity of every cell membrane in the body. The question is always about context and balance, not simply the number.
Total Serum Cholesterol: Why 0.0–4.9 mmol/L Is the NHS "Ideal"
All lipid values in UK clinical practice are expressed in millimoles per litre (mmol/L) — a measure of molecular concentration. The NHS and NICE (National Institute for Health and Care Excellence) set 5.0 mmol/L as the general population threshold, with below 4.0 mmol/L considered optimal for those with established cardiovascular risk.
The rationale comes from large population studies — most notably the Framingham Heart Study and later the INTERHEART study — which showed that as total cholesterol rises progressively above 5.0 mmol/L, the population-level risk of a first cardiovascular event (heart attack or stroke) increases. This is a statistical association in large groups, not a one-to-one individual prediction.
Important nuance: Total cholesterol in isolation is a relatively weak predictor of individual cardiovascular risk. A person with a total cholesterol of 7.0 mmol/L but high HDL, no insulin resistance, low triglycerides, and a favourable ratio may carry less actual risk than someone with a total of 5.2 mmol/L with low HDL and high triglycerides.
All values in mmol/L. NHS general population guidance (not cardiac risk patients).
Your Score: 7.3 mmol/L
At 7.3 mmol/L, your total serum cholesterol sits in the NHS "high" bracket. The NHS would not automatically prescribe statins at this level based on total cholesterol alone — instead it uses a 10-year cardiovascular risk tool called QRISK3, which incorporates age, sex, blood pressure, smoking, diabetes, deprivation score, ethnicity, and several other factors. A total cholesterol of 7.3 in a non-smoking, active man in his early 60s with no hypertension may still produce a 10-year risk below the 10% statin threshold.
It is also worth noting that a total cholesterol of 7.3 mmol/L can be consistent with Familial Hypercholesterolaemia (FH) — a genetic condition affecting approximately 1 in 250 people — though this requires further clinical assessment including LDL measurement and family history.
LDL Cholesterol: Why Over 2.9 mmol/L Raises a Flag
LDL (Low-Density Lipoprotein) carries cholesterol from the liver to peripheral tissues. It is not intrinsically dangerous — every cell in the body requires cholesterol delivered by LDL. The concern arises when LDL particles become oxidised or glycated (damaged by blood sugar and free radicals), at which point they can penetrate arterial walls and initiate an inflammatory process that over decades can contribute to plaque formation.
The NHS threshold of 3.0 mmol/L (sometimes written as >2.9 in some lab reports) reflects a general population cut-off. For people with existing cardiovascular disease or diabetes, NICE recommends a target of below 1.8 mmol/L. For the general healthy population, below 3.0 is considered acceptable, with below 2.0 being the ideal in higher-risk individuals.
LDL mmol/L. Thresholds are population-based and should be contextualised by overall risk.
A crucial distinction that standard NHS reporting does not capture: LDL particle size. Small, dense LDL particles (pattern B) are strongly atherogenic. Large, buoyant LDL particles (pattern A) are far less so. Low-carbohydrate diets tend to shift the pattern toward large buoyant LDL, even if the overall LDL number rises — which is why the number alone can be misleading in low-carb or keto-adapted individuals.
Non-HDL Cholesterol: Why Over 3.9 mmol/L Is Flagged
Non-HDL cholesterol is calculated simply as: Total Cholesterol minus HDL Cholesterol. It captures all the potentially atherogenic lipoprotein fractions in a single number — LDL, VLDL (Very Low-Density Lipoprotein), IDL (Intermediate Density Lipoprotein), and Lp(a). This makes it a more comprehensive and clinically useful marker than LDL alone, because VLDL and IDL are also involved in arterial plaque formation.
The NHS threshold of 4.0 mmol/L (flagged as high over 3.9) is derived from the same population risk data. Non-HDL cholesterol has been shown in several meta-analyses to be a stronger predictor of cardiovascular events than LDL alone, which is why it is now routinely reported.
| Marker | NHS Ideal / Target | Flag Threshold | What it captures |
|---|---|---|---|
| Total Cholesterol | <5.0 mmol/L | ≥5.0 mmol/L | All cholesterol-carrying particles |
| Total Cholesterol (John) | <5.0 mmol/L | 7.3 mmol/L ↑ | In NHS "high" band; context required |
| LDL Cholesterol | <3.0 mmol/L | ≥3.0 mmol/L | Primary carrier fraction; oxidised form atherogenic |
| HDL Cholesterol | ≥1.0 (M) / ≥1.2 (F) mmol/L | <1.0 / <1.2 mmol/L | Protective scavenger; higher is better |
| Non-HDL Cholesterol | <4.0 mmol/L | ≥4.0 mmol/L | All atherogenic particles combined |
| Triglycerides | <1.7 mmol/L | ≥1.7 mmol/L | Blood fat reflecting carb/sugar intake; insulin marker |
| Total : HDL Ratio | <4.0 | ≥4.0 | Balance of risk vs protective fraction |
The Cholesterol / HDL Ratio: Your Single Most Useful Number
The Total Cholesterol to HDL ratio divides your total cholesterol figure by your HDL figure. It expresses in a single number the balance between all the cholesterol circulating in your blood and the protective, anti-atherogenic HDL fraction.
For example, a person with total cholesterol of 7.3 and an HDL of 2.2 has a ratio of 3.32 — which is excellent. A person with total cholesterol of 5.0 and an HDL of 0.9 has a ratio of 5.56 — which is of much greater concern.
The ratio is considered by many cardiologists and lipidologists to be the most clinically meaningful single number from a standard lipid panel. It is a direct measure of how well your body manages cholesterol transport, not just how much is circulating.
| Ratio Range | NHS / Clinical Interpretation | Status |
|---|---|---|
| Below 3.5 | Excellent — very low cardiovascular risk | Excellent |
| 3.5 – 4.0 | Good — within normal protective range | Good |
| 4.0 – 5.0 | Borderline — average risk; monitor | Borderline |
| 5.0 – 6.0 | Elevated risk — lifestyle intervention advised | Elevated |
| Above 6.0 | High risk — clinical review warranted | High Risk |
Importantly: if your HDL is elevated (which is common on low-carbohydrate diets), your ratio may be excellent even with a high total cholesterol. This is why knowing your HDL value is essential before making any clinical judgement about a total cholesterol of 7.3.
An Ayurvedic Lens: Dosha Type and Lipid Tendencies
From an Ayurvedic standpoint, each constitutional type has a fundamentally different relationship with fat metabolism, digestive fire (agni), and the accumulation of metabolic waste products (ama). This doesn't replace clinical measurement — it provides a deeper framework for understanding predisposition and for personalising dietary and lifestyle responses.
- Typically lean with lower baseline cholesterol and triglycerides
- Metabolic irregularity — agni is variable (vishama agni)
- When Vata is aggravated, absorption becomes erratic; ama can accumulate in the nervous system and colon rather than the blood
- HDL may fluctuate; triglycerides can spike with irregular eating or high stress
- Most beneficial fats: ghee, sesame oil, whole milk — warm, grounding, regular meals
- Lipid concern is less typical unless underlying anxiety, insomnia, or irregular eating is chronic
- Strong agni (tikshna agni) — sharp, intense digestion and metabolism
- The liver is a Pitta organ — where cholesterol is synthesised, packaged and recycled
- Elevated LDL in a Pitta type is often driven by oxidative stress and inflammation — the liver produces more LDL under inflammatory conditions
- Pitta types more prone to oxidised LDL — the truly dangerous form — particularly with excess red meat, alcohol, or processed oils
- HDL is often adequate, but ratio can be skewed by elevated LDL
- Key: cooling, anti-inflammatory diet; bitter greens, coriander, coconut oil, pomegranate; avoid excessive stimulants
- Constitutionally most predisposed to elevated total cholesterol, LDL and triglycerides
- Slow, heavy agni (manda agni) — efficient storage, reduced fat burning
- Ama tends to accumulate as fatty deposits in tissues and vessels — the Ayurvedic correlate of atherogenesis
- HDL typically low — the protective fraction is suppressed by sedentary Kapha lifestyle
- Ratio often unfavourable — high total, low HDL
- Key interventions: intermittent fasting, spice-rich foods (ginger, pepper, turmeric), exercise, warm light meals; avoid dairy excess, sweet foods, daytime sleep
The Ayurvedic approach is not to normalise a number — it is to restore the metabolic intelligence (agni) that produces healthy lipid metabolism naturally. The treatment is upstream: correct the fire, the food choices, the timing and the lifestyle — and the numbers tend to follow.
Suggested "Good / Not Great" Ranges by Dosha Type
Conventional medicine applies population-average thresholds. These adjusted ranges reflect Ayurvedic metabolic tendencies — a guide to personalising how you read your lipid panel depending on constitution:
| Marker | Vata Range | Pitta Range | Kapha Range |
|---|---|---|---|
| Total Cholesterol | 4.0–6.5 (variable; not primary concern) | 3.5–5.5 (inflammation drives LDL; monitor closely) | 3.5–4.5 (strict; Kapha accumulates easily) |
| LDL Cholesterol | 2.0–3.5 (generally lower; focus on oxidation) | 1.5–2.5 (keep low; Pitta liver oxidises LDL) | 1.5–2.5 (Kapha deposits easily; keep low) |
| HDL Cholesterol | >1.2 (Vata can be low HDL with poor fat absorption) | >1.4 (higher HDL buffers Pitta inflammation) | >1.5 (Kapha needs higher HDL to compensate) |
| Non-HDL | <4.5 (acceptable if ratio good) | <3.5 (stricter; liver burden) | <3.0 (lowest tolerance) |
| Triglycerides | <1.5 (Vata converts carbs erratically) | <1.2 (keep very low; hepatic sensitivity) | <1.0 (Kapha stores sugar as fat rapidly) |
| Total : HDL Ratio | <4.5 (Vata: ratio can be variable) | <3.5 (Pitta benefits from strongly protective ratio) | <3.0 (Kapha: ratio is the key watchpoint) |
These dosha-adjusted ranges are offered as an integrative thinking tool, not clinical diagnostics. They reflect the constitutional metabolic tendencies described in classical Ayurvedic texts and align with emerging functional medicine approaches to individualised lipid interpretation. Always work with a qualified clinician for personal health decisions.
In Summary: The Five Numbers That Matter Most
- Total Cholesterol — context-dependent; do not interpret in isolation
- HDL — the higher, the better; your most protective single marker
- Triglycerides — the clearest dietary signal; should be below 1.5, ideally below 1.0 on LCHF
- Non-HDL — a better catch-all than LDL alone; keep below 3.9 mmol/L
- Total : HDL Ratio — your single most meaningful number; aim for below 3.5
A person with total cholesterol of 7.3 and an HDL of 2.0 or above has a ratio of 3.65 — a very reasonable figure. A person with 5.0 total and HDL of 0.9 has a ratio of 5.6 — significantly more concerning. The number in isolation tells only part of the story.