Quinoa is a healthy pseudocereal that is much more nutritious than other cereal products. A new study in the Nutrients journal reports the ability of quinoa to normalize glucose metabolism in the body, particularly among older adults with impaired glucose tolerance.
Study: Glycaemia Fluctuations Improvement in Old-Age Prediabetic Subjects Consuming a Quinoa-Based Diet: A Pilot Study. Image Credit: Iryna Melnyk / Shutterstock.com
Introduction
Type 2 diabetes mellitus (T2DM) causes millions of premature deaths each year. Prediabetes is a state in which blood glucose levels rise higher than expected after a meal but with a stable overall glycemic status.
The presence of prediabetes increases the risk of T2DM by 70%, with about 10% developing diabetes each year. The risk of T2DM is particularly high in those aged 65 years or more.
Quinoa is remarkable for its high protein content, which includes a complete set of all essential amino acids, as well as unsaturated fatty acids, minerals, and vitamins necessary for good health. In addition to its high carbohydrate and fiber content and low simple sugar concentration, quinoa is both nutritionally rich and associated with a low glycemic index, meaning it causes a slower and smaller rise in blood sugar compared to high-glycemic index foods.
Quinoa also contains a range of plant compounds that inhibit the digestion of fats and sugars in the human gut, which may reduce postprandial spikes in blood glucose.
The current study aimed to explore the effect of a diet rich in quinoa on controlling hyperglycemia and other metabolic risk factors. To this end, the researchers chose to use glycemic data collected by glucose sensors operating over extended periods with regular prespecified recording points. Such data can be represented and analyzed as a curve using the functional data analysis (FDA) approach that yields glucose concentrations over time.
Study findings
In this pilot study, all participants were at least 65 years old, had fasting glucose levels between 100 and 125 mg/dL, and did not have a history of diabetes. Additionally, all study participants consumed grains, legumes, and/or tubers on a daily basis.
After an initial four-week period during which the study participants consumed their regular diet, all nine subjects were switched to a quinoa-based diet, which was continued for an additional four weeks. All grains, grain-based products, legumes, and tubers were substituted with quinoa-based products without changing the overall composition of nutrients, except for the cereal part.
The study participants consumed quinoa, quinoa flakes, and quinoa flour, as well as biscuits, brioche, sponge cake, baguettes, sliced bread, and pasta. Each of these products had a quinoa content of 70% or greater.
All food products were provided to the subjects who commonly ate them. The study participants were also introduced to eight recipes for foods they commonly ate, with quinoa substituted for tubers, legumes, and grains.
With a mean age of 70 years, most participants were female with an overweight profile. In addition, most study participants had hypertension, about 45% had high blood lipids, and 33% had one or more close family members with diabetes.
At the end of the study, fasting glucose levels were lower at the start of the quinoa intervention compared to baseline; however, this reduction occurred during the regular diet phase, likely due to behavioral changes resulting from continuous glucose monitoring. Fasting glucose did not decline further during the quinoa diet phase. Weight and waist circumference also showed a slight decrease. Glycated hemoglobin (HbA1C) levels were also reduced by the end of the study, though the short duration and overlapping effects of the sensor use may have contributed to this change.
Nutritionally, the study participants consumed more carbohydrates during their regular diet, whereas they consumed more total lipids and saturated fat during the quinoa diet period. Energy intake, as well as intake of amino acids such as cystine, arginine, glutamic acid, and proline, also increased during the quinoa phase.
Further analysis showed that multiple nutrients were associated with enhanced or reduced glucose concentrations. The former was associated with gamma-tocopherol, soluble fiber, and the Oxygen Radical Absorbance Capacity (ORAC). The latter showed a link with theobromine, fatty acids, omega-6 polyunsaturated fatty acids (PUFA), fructose, phytic acid, citric acid, cellulose, and the proportion of total energy from protein. Insoluble dietary fiber was also associated with increased glucose levels later in the postprandial period.
Implications
The unique nutritional profile of quinoa, with higher fat and lower carbohydrate content compared to typical cereals, accounts for the difference in nutritional intake during the quinoa diet.
Eating more carbohydrates increases insulin levels, induces fat storage, and reduces the metabolic rate, thus promoting a vicious cycle of fat accumulation. A high-fat diet with the same number of calories reduces insulin secretion by triggering fat turnover in fat cells, thereby making free fatty acids available to the body for energy production. In addition, dietary proteins help build lean body mass during weight loss, thereby increasing energy expenditure and improving the body's overall composition.
In older prediabetic subjects, improving diet quality is more important than reducing body weight to achieve beneficial metabolic outcomes. The stabilization of blood sugar fluctuations with a quinoa diet may be attributed to the low glycemic index of this pseudocereal, in combination with the synergistic effect of its nutrient profile.
Definitive conclusions await future studies, as the participants in this study were able to observe their changing blood sugar levels in real time, which likely motivated better dietary patterns even before the intervention phase began.
Both higher energy intake and the increased fat content of quinoa were correlated with reduced glucose levels. This is likely due to the other nutrients present in quinoa that prevent a glycemic spike.
Since post-prandial hyperglycemia predicts the development of T2DM in many patients, the potential role of quinoa in delaying the development of this condition by reducing the spike in glucose levels following a meal is promising. Preliminary findings suggest that quinoa may help stabilize blood glucose levels in individuals with prediabetes, but larger, longer-term trials are required to confirm its role in diabetes prevention.
A diet rich in quinoa reduces postprandial glycemia, thanks to the joint action of different nutrients and the suppression of others consumed in a regular diet, which may help slow the progression to T2D.
Journal reference:
- Diaz-Rizzolo, D. A., Acar-Denizli, N., Kostov, B., et al. (2022). Glycaemia Fluctuations Improvement in Old-Age Prediabetic Subjects Consuming a Quinoa-Based Diet: A Pilot Study. Nutrients. doi.org/10.3390/nu14112331.
Article Revisions
- Jun 20 2025 - In response to a reader’s comment highlighting confusion around whether quinoa raises or lowers blood sugar, we have revised the relevant sentence in paragraph 3 to clarify that while quinoa does contain carbohydrates and thus raises blood sugar to some extent, its low glycemic index results in a slower and smaller rise compared to high-GI foods. Additionally, we have reviewed the full article to ensure consistency with the study’s findings. This included correcting an overstatement about quinoa reducing fasting glucose (which occurred prior to the intervention), clarifying the role of soluble and insoluble fiber in glycemic response, and softening speculative claims about diabetes prevention. These changes aim to enhance clarity, align the narrative with the study's actual results, and avoid overstating causality in this small, short-term pilot trial.
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