What is hs-CRP?

Cassie Wellock PA-C
Jun 5
5 min read

High-sensitivity C-reactive protein (hs-CRP) is a sensitive biomarker of systemic inflammation, measured via blood test using high-sensitivity assays that detect very low levels of CRP in the range of 0.1 to 10 mg/L. CRP itself is a pentameric acute-phase reactant protein produced primarily by hepatocytes (liver cells) in response to inflammatory cytokines—especially interleukin-6 (IL-6), interleukin-1β (IL-1β), and tumor necrosis factor-α (TNF-α).

Mechanism of CRP Production:

Inflammatory triggers (e.g., infection, tissue damage, oxidized LDL) activate macrophages and monocytes.
These immune cells release IL-6, which travels to the liver.
Hepatocytes respond by synthesizing CRP, which enters systemic circulation within 6–8 hours, peaking at 48 hours.

High-Sensitivity vs. Standard CRP:

Standard CRP detects levels ≥10 mg/L, useful in infection or acute illness.
hs-CRP detects chronic low-grade inflammation associated with atherogenesis, even when standard CRP is normal.

hs-CRP and Cardiovascular Risk: Pathophysiological Basis

1. Atherosclerosis as an Inflammatory Disease

Atherosclerosis is not merely a lipid-storage disease; it is fundamentally an inflammatory process. CRP is both:

A biomarker: Reflecting systemic inflammation.
A participant: Possibly contributing to endothelial dysfunction.

2. Role of hs-CRP in Endothelial Dysfunction

CRP can bind to oxidized LDL, promoting its uptake by macrophages → foam cell formation.
It activates endothelial cells to express adhesion molecules (VCAM-1, ICAM-1) and monocyte chemoattractant protein-1 (MCP-1).
CRP reduces nitric oxide (NO) bioavailability → impairs vasodilation.

3. hs-CRP and Plaque Instability

Elevated hs-CRP correlates with plaque vulnerability, characterized by a thin fibrous cap and large lipid core.
It’s predictive of plaque rupture, thrombosis, and acute coronary syndromes.

Considerations

Nonspecific marker: Elevated in autoimmune diseases, infections, cancer, obesity
Single readings not sufficient: Best assessed with 2 measurements, when free of acute illness
Strongly influenced by adiposity: Visceral fat secretes IL-6 → hepatic CRP synthesis

hs-CRP, Visceral Adiposity, and Fatty Liver Disease

1. Visceral Adipose Tissue (VAT) and Systemic Inflammation

Visceral fat is metabolically active, functioning as an endocrine organ that secretes pro-inflammatory cytokines—especially:

Interleukin-6 (IL-6)
Tumor Necrosis Factor-α (TNF-α)
Monocyte Chemoattractant Protein-1 (MCP-1)

These cytokines stimulate the hepatic synthesis of CRP, particularly IL-6, which is the primary regulator of CRP gene expression in hepatocytes.

2. Non-Alcoholic Fatty Liver Disease (NAFLD)

NAFLD is tightly linked with metabolic syndrome and low-grade inflammation, and is both a cause and consequence of elevated hs-CRP.

Mechanism:

Hepatic steatosis → mitochondrial dysfunction → lipotoxicity → Kupffer cell activation → increased IL-6 and TNF-α
These inflammatory cytokines increase hepatic CRP gene transcription

🍭 hs-CRP and Dietary Inflammation: Alcohol, Sugar, and Processed Foods

1. Alcohol

Excess alcohol increases endotoxemia, gut permeability, and inflammatory cytokine release.

Mechanism:

Alcohol-induced gut barrier disruption → LPS translocation → TLR4 activation in liver and immune cells → IL-6 release → ↑ hs-CRP

2. Processed Foods and Industrial Seed Oils

Processed foods high in trans fats, refined carbohydrates, and omega-6 fatty acids (linoleic acid) promote inflammatory pathways.
These foods increase oxidative stress, glycation end products, and NF-κB activation, which stimulate IL-6 and CRP production.

3. Added Sugar and High-Glycemic Diets

High intake of sugar and refined carbs leads to:

Hyperglycemia → oxidative stress
Insulin resistance → adipocyte dysfunction
AGE formation and chronic immune activation

This cascade leads to increased IL-6 and TNF-α, which drive CRP synthesis.

How to Lower hs-CRP

1. Mediterranean Diet

Daily Staples:

Extra virgin olive oil (EVOO): 2–4 tbsp/day
Fatty fish (salmon, sardines, mackerel): 3–4x/week
Legumes (lentils, chickpeas): 1 cup, 3–4x/week
Nuts (walnuts, almonds): 1–2 oz/day
Whole grains (quinoa, oats, barley): 1–2 servings/day
Fresh vegetables (especially leafy greens, cruciferous): ≥5 servings/day
Berries and fruits (esp. polyphenol-rich): 1–3 servings/day

2. Polyphenol-Rich Foods

Effect: Reduce oxidative stress and inhibit NF-kB, a key inflammatory pathway.

Include:

Berries (blueberries, raspberries, strawberries)
Pomegranate, tart cherry, and citrus fruits
Dark chocolate (min. 70% cacao, 1 oz max/day)
Green tea or matcha (1–3 cups/day)

3. Omega-3 Fatty Acids

Effect: Compete with omega-6s in the arachidonic acid pathway, reducing pro-inflammatory cytokines and lowering hs-CRP.

Sources:

EPA/DHA from fish or fish oil (goal: 2–4g/day combined)
Ground flaxseed or chia (ALA, though less potent)
Algae-based omega-3s (for plant-based diets)

4. High-Fiber Foods (≥35-40g/day)

Effect: Improves gut microbiota and short-chain fatty acid production, which suppresses inflammation.

Best sources:

Oats, barley, quinoa
Lentils, black beans, chickpeas
Flaxseed, psyllium husk
Artichokes, asparagus, leafy greens
Avocado

5. Avoid or Minimize Pro-Inflammatory Foods

Evidence: These elevate hs-CRP, IL-6, and TNF-α.

Limit or eliminate:

Refined carbs (white bread, pastries, soda)
Added sugars (fructose-rich syrups, sweetened drinks)
Industrial seed oils (soybean, corn, sunflower oils)
Processed meats (bacon, sausage, deli meats)
Trans fats (commercial baked goods, margarine)
Alcohol in excess (>1 drink/day women, >2 men)

Optional Supplements (Evidence-Supported for Lowering hs-CRP)

Supplement	Dosage	Evidence Source
Omega-3 (EPA/DHA)	2–4 g/day	Calder et al., Biochem Soc Trans 2017
Curcumin (with piperine)	500–1000 mg/day	Panahi et al., Phytother Res 2014
Magnesium (glycinate/citrate)	300–400 mg/day	Zheltova et al., J Med Life 2016
Vitamin D3	2000 IU/day (optimize levels)	Zittermann et al., Nutrients 2015
Fiber (psyllium, inulin)	5–10 g/day	Soliman, Nutrients 2019

Sample Anti-Inflammatory Day

Breakfast:

Steel-cut oats + blueberries + ground flax + walnuts
Green tea or black coffee (no sugar)

Lunch:

Quinoa salad w/ olive oil, chickpeas, kale, cucumbers, red peppers
Side of pomegranate seeds

Snack:

Small handful of almonds
Tart cherry juice (unsweetened, 4 oz)

Dinner:

Grilled salmon over roasted Brussels sprouts and sweet potato
Arugula salad with EVOO and lemon

Tracking Progress

Recheck hs-CRP every 3–6 months to evaluate dietary impact. Target:

<1.0 mg/L = low risk
1–3 mg/L = moderate
>3.0 mg/L = high inflammation

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