# Oca (Oxalis tuberosa)

**Canonical URL:** https://ingredients.hermeticasuperfoods.com/ingredients/oca
**Data Source:** Hermetica Superfoods Ingredient Encyclopedia
**Updated:** 2026-03-24
**Evidence Score:** 2 / 10
**Category:** Other
**Also Known As:** Oxalis tuberosa, New Zealand yam, Wood sorrel tuber, Oca del Peru, Ibia, Quiba, Apilla, Andean wood sorrel

## Overview

Oca (Oxalis tuberosa) is an Andean root vegetable containing ocatin, a novel defensin-like storage protein with documented [antimicrobial](/ingredients/condition/immune-support) and nutritional properties. Its oxalic acid, anthocyanin, and phenolic compound content contribute to [antioxidant activity](/ingredients/condition/antioxidant), though human clinical evidence remains limited.

## Health Benefits

• Nutrient-dense food source recognized by USDA classification (evidence quality: traditional/observational)
• Contains ocatin, a novel storage protein contributing to nutritional value (evidence quality: biochemical analysis only)
• [Antioxidant](/ingredients/condition/antioxidant) potential suggested by related Oxalis species through ROS reduction (evidence quality: indirect, not specific to O. tuberosa)
• Starch modification shows improved emulsifying properties for food applications (evidence quality: in vitro food science studies)
• Traditional staple crop providing sustenance in Andean regions for millennia (evidence quality: historical/cultural documentation)

## Mechanism of Action

Ocatin, a 15 kDa storage protein isolated from oca tubers, exhibits antifungal activity by disrupting fungal cell membrane integrity and inhibiting chitin-binding pathogens. Anthocyanins and polyphenols present in the tuber's pigmented varieties scavenge [reactive oxygen species](/ingredients/condition/antioxidant) (ROS) and may inhibit lipid peroxidation via free radical chain-breaking mechanisms. Oxalic acid content modulates calcium bioavailability by forming insoluble calcium oxalate complexes in the gut, which is a relevant consideration for mineral absorption.

## Clinical Summary

No controlled human clinical trials have been conducted specifically on oca supplementation or extracts as of current literature. Nutritional analysis studies confirm oca tubers provide approximately 70–80% carbohydrates, moderate vitamin C (around 18–24 mg per 100g fresh weight), and meaningful potassium levels, based on USDA and FAO compositional data. In vitro studies on ocatin demonstrated inhibition of fungal growth against Fusarium and Botrytis species, though these findings have not been translated to human or animal trial endpoints. Evidence for human health benefits remains at the traditional, observational, and biochemical analysis level, requiring rigorous clinical investigation before therapeutic claims can be substantiated.

## Nutritional Profile

Oca (Oxalis tuberosa) is a starchy tuber with moderate caloric density (~70-80 kcal per 100g fresh weight). Macronutrients: carbohydrates dominate at approximately 15-17g/100g (fresh weight), primarily as starch with amylose content varying by cultivar (typically 20-30% of total starch); protein content is relatively notable for a tuber at 1.0-1.5g/100g fresh weight, featuring the novel storage protein ocatin (~20-30% of total protein, approximately 21-22 kDa molecular weight) with reported antifungal properties; fat content is low at <0.5g/100g; dietary fiber approximately 1.5-2.5g/100g. Micronutrients: potassium is the predominant mineral at approximately 200-300mg/100g fresh weight; calcium present at 20-40mg/100g; phosphorus at 36-50mg/100g; iron at 0.5-1.0mg/100g (bioavailability potentially limited by oxalate content). Vitamin C is notably present at approximately 20-40mg/100g fresh weight, though heat-sensitive and reduced by cooking. Oxalic acid is a significant antinutritional factor at 50-900mg/100g depending on cultivar and preparation (sun-drying, a traditional practice called 'caya', substantially reduces oxalate levels and increases sugar content via starch conversion). Bioactive compounds include flavonoids and polyphenols consistent with the Oxalis genus, though species-specific quantification for O. tuberosa remains limited in peer-reviewed literature. Anthocyanins present in pigmented cultivars (purple/red varieties). Bioavailability note: high oxalate content may chelate calcium and iron, reducing their net absorption; traditional processing methods (sun exposure, freezing, boiling) measurably improve nutritional availability.

## Dosage & Preparation

No clinically studied dosage ranges exist for Oca as a supplement. Food science studies have modified Oca starch at 3% OSA concentration for industrial applications, but this does not translate to clinical dosing. Consult a healthcare provider before starting any new supplement.

## Safety & Drug Interactions

Oca contains moderate-to-high levels of oxalic acid (ranging from 200–900 mg per 100g depending on variety and preparation), which may increase kidney stone risk in individuals predisposed to calcium oxalate nephrolithiasis and should be consumed cautiously by those with chronic kidney disease. Traditional Andean preparation methods including sun-drying (freeze-drying in natural conditions) and boiling reduce oxalate content significantly and improve safety. No documented drug interactions have been formally studied, though high oxalate intake theoretically reduces absorption of calcium, magnesium, and zinc, which could interact with supplementation regimens for these minerals. Pregnant or lactating individuals should adhere to food-level consumption rather than concentrated extract forms, given the absence of safety data in these populations.

## Scientific Research

No human clinical trials, randomized controlled trials, or meta-analyses were identified for Oca (Oxalis tuberosa) in the available research. Studies are limited to in vitro biochemical assays, food science research on starch properties, and nutritional analyses, with no PubMed PMIDs available for human therapeutic outcomes.

## Historical & Cultural Context

Oca has been cultivated by Andean indigenous peoples, including Inca and pre-Inca cultures, for over 4,000 years as a staple food tuber. It was valued primarily for its nutrient density as a food source rather than for formalized medicinal applications in traditional medicine systems.

## Synergistic Combinations

Other Andean tubers, low-oxalate vegetables, calcium supplements (to bind oxalates), vitamin B complex, [digestive enzyme](/ingredients/condition/gut-health)s

## Frequently Asked Questions

### What is ocatin and what does it do in the body?

Ocatin is a 15 kDa defensin-like storage protein unique to Oxalis tuberosa tubers, first characterized in biochemical studies for its antifungal properties. It disrupts the cell membrane integrity of pathogenic fungi such as Fusarium oxysporum, though all evidence to date comes from in vitro laboratory studies. Its role as a direct therapeutic agent in humans has not been clinically evaluated.

### How much oxalic acid does oca contain and is it safe to eat?

Raw oca tubers contain approximately 200–900 mg of oxalic acid per 100g, depending on the variety and growing conditions, placing them in the moderate-to-high oxalate food category. Boiling, soaking, and traditional sun-drying methods can reduce oxalate content by 30–60%, making prepared oca safer for regular consumption. Individuals with a history of calcium oxalate kidney stones or chronic kidney disease should limit intake and consult a healthcare provider.

### Does oca have antioxidant properties?

Pigmented oca varieties contain anthocyanins and phenolic compounds, classes of molecules demonstrated to scavenge reactive oxygen species and inhibit lipid peroxidation in related Oxalis species and other root vegetables studied in vitro. Vitamin C content averaging 18–24 mg per 100g fresh weight also contributes to antioxidant capacity. However, no human bioavailability or antioxidant efficacy trials using oca specifically have been published.

### Can oca be taken as a supplement or is it only a food?

Currently, oca is consumed almost exclusively as a whole food in Andean regions and has not been developed into a commercially standardized dietary supplement. No established supplemental dosage, standardized extract, or certified ocatin concentration is commercially available. Whole tuber consumption at typical dietary quantities (100–200g per serving) represents the only evidence-informed method of intake.

### How does oca compare nutritionally to potato?

Oca tubers provide approximately 70–80% carbohydrates on a dry weight basis, similar to potato, but contain notably higher levels of oxalic acid and a more diverse phenolic profile in pigmented varieties. Protein content in oca averages 4–9% of dry weight, slightly higher than common potato varieties, with ocatin comprising a unique fraction absent in potato. Potassium content is comparable to potato at roughly 400–500 mg per 100g, while vitamin C levels are broadly similar, making oca a nutritionally competitive but oxalate-richer alternative.

### Is oca safe to eat during pregnancy and breastfeeding?

Oca is a traditional food in Andean cultures where it has been safely consumed for centuries, including by pregnant and nursing women, suggesting a favorable safety profile during these periods. However, its oxalic acid content warrants moderation, as high oxalate intake during pregnancy may theoretically affect mineral absorption; consulting with a healthcare provider about appropriate consumption levels is recommended. No clinical studies have specifically evaluated oca safety in pregnancy, so evidence relies on traditional use rather than formal clinical research.

### What is the most effective way to prepare oca to maximize its nutritional value?

Cooking oca—whether boiling, roasting, or steaming—may reduce oxalic acid content while preserving water-soluble nutrients and making starches more digestible, though minimal research exists on optimal preparation methods specific to O. tuberosa. Raw oca retains higher levels of heat-sensitive compounds, but cooking is traditionally preferred in Andean regions and may improve overall bioavailability of minerals by reducing antinutrient interference. The specific preparation method (whole, peeled, or cut) likely has minimal impact compared to cooking versus raw consumption.

### Does oca interact with medications used to treat kidney disease or calcium metabolism disorders?

Because oca contains oxalic acid, which binds to calcium and may affect mineral absorption, individuals taking medications for kidney disease or disorders affecting calcium and phosphorus regulation should consult their healthcare provider before regular consumption. Those on potassium-sparing diuretics or calcium-modulating therapies may need to monitor oca intake, as the tuber's nutrient profile could theoretically influence mineral balance. No formal drug interaction studies exist for oca, so caution should be based on its oxalate content and individual medical conditions rather than documented interactions.

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