Horchata: two different drinks, neither one tested

No randomised trial has tested horchata, of either kind. The name covers two drinks, one milled from tiger nut tubers in Spain and one from rice in Latin America, and the closest evidence that exists is trials of other rice beverages. In 13 overweight and obese men of mean age 24.5, a drink made from 2 g of riceberry rice extract in 400 mL lowered the rise in blood glucose, insulin and serum triglycerides after a high-carbohydrate meal. It changed nothing in their ratings of hunger or fullness. That was one meal in 13 young men, and a 2 g extract in water is a long way from horchata, which is milled grain or tuber and usually sweetened. In 40 adults with metabolic syndrome in Okinawa, 4 weeks of a fermented brown rice beverage raised three beneficial gut species where the same beverage made from white rice did not. That trial had a single arm with no untreated control, and its outcome was bacterial abundance rather than anything a person feels. Every human report of harm on this page is a small child given a plant drink in place of milk, and in one of those cases the infant died. What a sweetened glass of horchata does to anybody has never been measured, and the sugar in it is the part most readers are asking about.

The numbers, per 100 g

How much is actually in it

• In a market survey of 22 tiger nut horchata samples from Spanish and Belgian supermarkets, only 1 carried detectable aflatoxin B1, and that one sat at the limit of quantitation. — 22 retail samples of tiger nut based horchata from Spanish and Belgian supermarkets, analysed by immunoaffinity cleanup with HPLC and fluorescence detection (n = 22) Evidence C source
  1 of 22 samples contained aflatoxin B1, at the quantification limit of 0.06 microgram per kg; mean recovery of the method 88 per cent with a coefficient of variation of 9 per cent

What cooking and storage change

• In 40 Okinawans with metabolic syndrome, 4 weeks of a fermented brown rice beverage shifted the gut microbiota where the same beverage made from white rice did not. — 40 adults with metabolic syndrome in Okinawa, 4 weeks, one daily beverage replacing the main meal (n = 40) Evidence B source
  3 beneficial species rose with the brown rice beverage and not with the white: Lactobacillales bacterium DJF B280 (P = 0.005), Butyrate producing bacterium A2 207 (P = 0.012) and Firmicutes bacterium DJF VP44 (P = 0.038)

What it does to your health

• In 13 overweight and obese men, a rice beverage made from 2 g of riceberry rice extract in 400 mL lowered the glucose, insulin and triglyceride rise after a high-carbohydrate meal. — 13 overweight and obese men, mean age 24.5 years, mean BMI 25.9, randomised crossover, blood sampled up to 6 hours after the meal (n = 13) Evidence B source
  Lower incremental area under the curve for postprandial plasma glucose, insulin, malondialdehyde and serum triglycerides against control; antioxidant capacity measures rose; no difference in hunger, fullness or satiety ratings

What people believe that the data does not support

• The 2025 systematic review of tiger nut names evidence-based validation of health claims as work still to be done, alongside molecular breeding and waste reuse. — systematic review of tiger nut literature on composition, oil accumulation, extraction technology and by-product use (n = review) Evidence D source
  No health outcome estimated; the review sets validation of health claims as a future research target rather than reporting it as achieved

Who this works differently for

• In about 8300 Americans surveyed in NHANES 2003 to 2010, rice beverage and rice milk showed the largest association of any food with urinary monomethylarsonic acid in adults. — about 8300 NHANES participants aged 6 years and over, 2003 to 2010, urinary arsenic species against 24-hour dietary recall, age-stratified and adjusted for confounders (n = about 8300) Evidence C source
  Rice beverage and rice milk had the largest association with urinary monomethylarsonic acid among adults; median urinary methylated arsenic ranged 0.56 to 3.52 micromol per mol creatinine; children 6 to 11 years had the highest concentrations of all age groups
• A 22-month-old boy drinking 1.5 L of rice beverage a day developed kwashiorkor, because the drink supplied 0.3 g of protein per kg a day, which is 25 per cent of the recommended allowance. — one 22-month-old boy weaned onto a rice beverage after breastfeeding to 13 months, 1.5 L daily, poor intake of solid food (n = 1) Evidence D source
  Protein intake 0.3 g per kg per day, 25 per cent of the recommended dietary allowance, while calorie intake reached 72 per cent of the recommendation; serum albumin 1.0 g/dL; generalised oedema resolved within 3 weeks of refeeding
• A French series of 4 infants fed plant beverages instead of milk included 2 fed rice drinks for 2 months, one with kwashiorkor and albumin at 7 g/L and one with haemoglobin at 35 g/L. — 4 infants aged 2.5 to 14 months fed vegetable beverages (rice, almond, nut, chestnut, soy) in place of milk for 3 weeks to 2 months (n = 4) Evidence C source
  Case 1 hypoalbuminaemia at 7 g/L with kwashiorkor and severe sepsis; case 2 iron and vitamin B12 deficiency with haemoglobin 35 g/L; case 3 metabolic alkalosis from sodium and chloride deficiency; case 4 sodium 96 mmol/L with coma, and the infant died
• An infant given rice beverage developed food protein induced enterocolitis with vomiting, low blood pressure and metabolic acidosis, confirmed by a double blind placebo controlled challenge. — one infant presenting to an emergency department after ingesting rice beverage, rechallenged under double blind placebo controlled conditions with hydrolysed formula as placebo (n = 1) Evidence D source
  Vomiting, watery stools, hypotension and metabolic acidosis on presentation; the rice based formula reproduced emesis, diarrhoea and lethargy on challenge, with raised neutrophils and faecal eosinophils

The bottom line

On contamination, a market survey of 22 retail tiger nut horchatas from Spanish and Belgian supermarkets found aflatoxin B1 in 1 sample, and that one sat exactly at the quantification limit of the method, 0.06 microgram per kg. Those were 22 samples from 2 countries in 2006, a snapshot rather than surveillance, and mould toxin is the question asked of this drink because tiger nut is a tuber stored dry. Nothing in that survey speaks to rice horchata. A 2025 systematic review of the whole tiger nut crop still lists evidence-based validation of health claims as work for the future, which is negative evidence of the useful kind, since the health section of that review is mechanistic and carries no human outcome. No regulator has looked at horchata by name, and we found no study of what a person absorbs from this drink. Every caution on this page is about small children, and none of it sits under a safety heading, because all of it comes from rice drinks given to infants. A 22-month-old boy drinking 1.5 L of a rice beverage a day developed kwashiorkor, since the drink supplied 0.3 g of protein per kg a day, 25 per cent of the recommended allowance, while his calorie intake reached 72 per cent of it. That is one child whose intake of solid food was very poor, so the cause was the whole diet. A French series of 4 infants fed plant drinks in place of milk for 3 weeks to 2 months included 2 on rice drinks, one with albumin at 7 g/L and kwashiorkor and one with haemoglobin at 35 g/L. In the fourth case the infant had sodium at 96 mmol/L, went into coma and died. Four selected cases say nothing about how often any of this happens. One infant developed food protein induced enterocolitis after a rice beverage, with vomiting, low blood pressure and metabolic acidosis, and a double blind placebo-controlled challenge reproduced it. That was the first case of the kind described from a rice beverage, which means rare and not negligible. In about 8300 Americans surveyed in NHANES between 2003 and 2010, rice beverage and rice milk carried the largest association of any food with urinary monomethylarsonic acid among adults, measured against a single day of dietary recall. Urinary arsenic marks exposure rather than harm, and children aged 6 to 11 had the highest concentrations of any age group in that survey. The short version for a parent is that a rice drink is not milk, and a small child should not be living on one.

Sources

1. hrch-r4-07 · market survey
   The method was applied to conduct a small market survey for a beverage named 'horchata' that is frequently consumed by parts of the population in Southern Europe. Twenty-two samples from Spanish and Belgian supermarkets were analysed. As a result, only one sample was found to contain aflatoxin B1 at the limit of quantitation of the method.
   Food Addit Contam, 2006 · checked 2026-09-24
2. hrch-r4-02 · randomised controlled trial
   Using a 4-week randomized, single-arm study design, subjects (n = 40) were advised to consume a daily fermented brown rice beverage (BA) or fermented white rice beverage (WA) as a replacement of their main meal...This study demonstrates that consumption of BA is effective to beneficially modulate the gut microbiota compared with WA in patients with MetS.
   Nutr Res, 2022 · checked 2026-09-24
3. hrch-r4-01 · randomised crossover trial
   They consumed an HCMF meal with or without RRB (2 g of riceberry rice extract powder/400 ml)...The ingestion of the HCMF meal accompanied by RRB had a lower incremental area under the curve (iAUC) for postprandial plasma glucose, insulin, malondialdehyde (MDA) and serum triglyceride concentrations when compared to the control.
   Food Funct, 2022 · checked 2026-09-24
4. hrch-r4-08 · systematic review
   It not only summarizes existing knowledge, but also charts a strategic roadmap for future research on tiger nuts, emphasizing molecular breeding, circular bioeconomy, and evidence-based health claim validation to unlock the full industrial potential of tiger nuts.
   J Food Sci, 2025 · checked 2026-09-24
5. hrch-r4-03 · cross-sectional survey analysis
   And, for adults, rice beverage/milk (DMA, MMA)...For MMA, rice beverage/milk (adults) and rice cakes/crackers (children, adolescents) had the largest associations.
   PLoS One, 2014 · checked 2026-09-24
6. hrch-r4-04 · case report
   On average, he consumed 1.5 L of this drink daily...As this rice beverage, which was fallaciously referred to as rice milk, is extremely low in protein content, the resulting daily protein intake of 0.3 g/kg/day was only 25% of the recommended dietary allowance.
   Pediatrics, 2001 · checked 2026-09-24
7. hrch-r4-05 · case series
   Case 1: a 9 month-old infant fed by a rice beverage for 2 months presented hypoalbuminemia (7 g/L) with kwashiorkor syndrome complicated by severe sepsis. Case 2: a 14 month-old infant fed by a rice beverage for 2 months had iron and vitamin B12 deficiency with deep anemia (Hb 35 g/L) and tissue hypoxia (hyperlactacidemia).
   Presse Med, 2013 · checked 2026-09-24
8. hrch-r4-06 · case report
   Infant with FPIES presented to our emergency department with vomiting, watery stools, hypothension and metabolic acidosis after ingestion of rice beverage...For this reason, the use of rice beverage as cow's milk substitute for the treatment of non IgE-mediated food allergy should be avoided.
   Ital J Pediatr, 2013 · checked 2026-09-24