# Kenyan SL28 (Coffea arabica 'SL28')

**Canonical URL:** https://ingredients.hermeticasuperfoods.com/ingredients/kenyan-sl28
**Data Source:** Hermetica Superfoods Ingredient Encyclopedia
**Updated:** 2026-03-30
**Evidence Score:** 2 / 10
**Category:** Coffee Cultivars
**Also Known As:** SL28, Scott Labs 28, SL-28, Kenyan SL-28, Scott Agricultural Laboratories 28, SL28 cultivar, SL28 variety

## Overview

Kenyan SL28 (Coffea arabica 'SL28') is a high-altitude coffee cultivar containing chlorogenic acids and caffeine as primary bioactives. These compounds may support [glucose metabolism](/ingredients/condition/weight-management) and provide [anti-inflammatory](/ingredients/condition/inflammation) effects through [antioxidant](/ingredients/condition/antioxidant) pathways.

## Health Benefits

• [Anti-inflammatory](/ingredients/condition/inflammation) effects shown in vitro using Kenya AA green coffee extracts (potentially including SL28-like cultivars) at 5-100 μg/mL concentrations (preliminary evidence only)
• Potential [glucose metabolism](/ingredients/condition/weight-management) support suggested by general Kenyan coffee studies, though SL28-specific data lacking (evidence quality: insufficient)
• Higher trigonelline content (48.5 g/kg) compared to other cultivars may provide enhanced [antioxidant activity](/ingredients/condition/antioxidant) (theoretical benefit, no clinical evidence)
• Natural source of chlorogenic acids comparable to other arabica cultivars (no SL28-specific clinical evidence)
• Traditional stimulant effects from general coffee consumption apply, though no SL28-specific studies exist (evidence quality: not established)

## Mechanism of Action

Chlorogenic acids in SL28 coffee inhibit glucose-6-phosphatase and α-glucosidase enzymes, potentially improving [glucose metabolism](/ingredients/condition/weight-management). The compounds also activate Nrf2 [antioxidant](/ingredients/condition/antioxidant) pathways and inhibit NF-κB signaling, reducing [inflammatory](/ingredients/condition/inflammation) cytokine production. Caffeine enhances these effects by blocking adenosine receptors and stimulating lipolysis.

## Clinical Summary

Limited in vitro studies using Kenya AA green coffee extracts (potentially including SL28-like cultivars) showed [anti-inflammatory](/ingredients/condition/inflammation) effects at 5-100 μg/mL concentrations. General Kenyan coffee studies suggest [glucose metabolism](/ingredients/condition/weight-management) benefits, but SL28-specific clinical data is lacking. Most evidence comes from broader arabica coffee research rather than this specific cultivar. Human trials specifically testing SL28 are needed to confirm therapeutic effects.

## Nutritional Profile

{"macronutrients": {"protein": "Approximately 10-12 g/kg", "fiber": "Approximately 20-25 g/kg"}, "micronutrients": {"vitamins": {"Vitamin B3 (Niacin)": "Approximately 10-15 mg/kg"}, "minerals": {"Magnesium": "Approximately 1.2-1.5 g/kg", "Potassium": "Approximately 12-14 g/kg"}}, "bioactive_compounds": {"caffeine": "Approximately 10-15 g/kg", "trigonelline": "48.5 g/kg", "chlorogenic_acids": "Approximately 50-60 g/kg"}, "bioavailability_notes": "The bioavailability of these compounds can vary based on preparation methods, such as brewing time and temperature. Trigonelline and chlorogenic acids are known to degrade with high heat, affecting their concentrations in brewed coffee."}

## Dosage & Preparation

No clinically studied dosage ranges exist for Kenyan SL28. In vitro studies used Kenya AA green coffee extracts at 5-100 μg/mL in cell cultures, with toxicity observed at 1000 μg/mL, but these concentrations cannot be translated to human consumption. General coffee preparation methods apply, but no standardized extracts or supplements have been studied. Consult a healthcare provider before starting any new supplement.

## Safety & Drug Interactions

SL28 coffee appears generally safe when consumed in normal amounts, with similar caffeine content to other arabica varieties (1-2% by weight). Excessive intake may cause caffeine-related side effects including anxiety, [insomnia](/ingredients/condition/sleep), and elevated heart rate. May interact with blood thinners due to chlorogenic acid content and can interfere with iron absorption. Pregnant women should limit caffeine intake to under 200mg daily.

## Scientific Research

No human clinical trials, randomized controlled trials, or meta-analyses specifically examining Kenyan SL28 coffee were identified in the available research. The only relevant study examined Kenya AA green coffee bean extracts in RAW 264.7 cells, showing [anti-inflammatory](/ingredients/condition/inflammation) effects through inhibition of NO production, iNOS, and COX-2 expression at 5-100 μg/mL, but this lacks human data and specific attribution to SL28.

## Historical & Cultural Context

Kenyan SL28 has no documented history in traditional medicine systems, as it was specifically bred in the 1930s for agricultural traits including yield, quality, and drought resistance rather than medicinal purposes. While coffee (Coffea arabica) has broader traditional uses in East African cultures for stimulation, SL28-specific medicinal applications are absent from historical records.

## Synergistic Combinations

Green tea extract, L-theanine, Rhodiola rosea, Ashwagandha, Cordyceps

## Frequently Asked Questions

### How much caffeine does SL28 coffee contain compared to other varieties?

SL28 contains approximately 1-2% caffeine by weight, similar to other arabica cultivars but generally lower than robusta varieties. A typical 8oz cup provides 80-100mg of caffeine depending on brewing method and bean preparation.

### What makes SL28 different from regular arabica coffee for health benefits?

SL28's high-altitude growing conditions in Kenya may concentrate chlorogenic acids and antioxidants compared to lower-altitude arabica varieties. However, specific comparative studies on bioactive compound levels between SL28 and other cultivars are limited.

### Can SL28 green coffee extract help with weight loss?

While general green coffee extract studies suggest modest weight loss effects (2-5 pounds over 8-12 weeks), no specific studies have tested SL28 cultivar for weight management. The chlorogenic acid content may support metabolism, but evidence is preliminary.

### Is SL28 coffee safe for people with diabetes?

SL28 coffee may actually benefit glucose metabolism due to chlorogenic acids that inhibit glucose absorption enzymes. However, diabetics should monitor blood sugar responses and consult healthcare providers, especially when adding cream or sweeteners.

### How should SL28 coffee be prepared to maximize health benefits?

Light to medium roasting preserves more chlorogenic acids than dark roasting, which can reduce these compounds by 50-70%. Cold brewing or shorter extraction times may also retain more beneficial compounds compared to prolonged hot brewing methods.

### What is trigonelline and why is SL28 coffee's higher trigonelline content significant?

Trigonelline is a naturally occurring alkaloid compound found in coffee that may support glucose metabolism and have anti-inflammatory properties. SL28 contains approximately 48.5 g/kg of trigonelline, which is notably higher than many other arabica cultivars, potentially making it a more concentrated source of this bioactive compound. However, human clinical trials specifically examining SL28's trigonelline content and its health effects remain limited.

### Is SL28 coffee safer than other arabica varieties for people sensitive to caffeine?

SL28 contains similar caffeine levels to standard arabica varieties (approximately 1.2–1.5% by weight), so it does not provide a caffeine-reduction advantage over other arabica cultivars. If you are caffeine-sensitive, SL28 does not offer a meaningful safety benefit compared to other arabica options; decaffeinated versions or lower-caffeine robusta blends would be more appropriate alternatives.

### What does current research reveal about SL28's anti-inflammatory effects in humans?

Existing evidence for SL28's anti-inflammatory effects comes primarily from in vitro laboratory studies using green coffee extracts at 5–100 μg/mL concentrations, with preliminary data suggesting potential benefits. However, human clinical trials specifically investigating SL28's anti-inflammatory action are absent, making it premature to claim therapeutic effects in people. More robust, peer-reviewed human studies are needed before definitive health claims can be made about this cultivar.

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