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Glycine Max

Also known as: Soybean, Soybean seed, Glycine max

Overview

Glycine max, commonly known as soybean, is a widely cultivated plant used as a food source and a dietary supplement ingredient. It is rich in essential nutrients including proteins, isoflavones (phytoestrogens), lecithins, saponins, and fiber. This ingredient is primarily researched for its potential to support cardiovascular health, regulate metabolic processes, and offer anti-obesity effects. Additionally, it is explored for its role in muscle repair and anti-inflammatory properties. While there is a substantial body of clinical and preclinical research, including systematic reviews on soy isoflavones and soybean protein, the overall evidence quality varies due to heterogeneity across studies. Glycine max is a versatile ingredient with a moderate level of research maturity.

Benefits

Glycine max offers several evidence-based benefits. For metabolic and endocrine health, oral glycine (a component of Glycine max) at 5g three times daily for three months has shown to improve insulin response, decrease HbA1c, and reduce insulin resistance markers in type 2 diabetes patients. While effects in metabolic syndrome patients were mixed, some subgroups experienced improved HDL and lowered LDL cholesterol. For cardiovascular health, soybean protein and its bioactive components have been demonstrated to improve serum lipid profiles by lowering triglycerides and LDL cholesterol while increasing HDL cholesterol, thereby reducing cardiovascular risk. Regarding muscle and exercise, glycine supplementation may enhance muscle protein synthesis, reduce fatigue, and support muscle repair, though human evidence is limited and inconclusive, with most data coming from animal or in vitro studies. Furthermore, dietary glycine may possess geroprotective potential by reducing inflammation and oxidative stress, supported by animal models and some human data, suggesting benefits for longevity.

How it works

Glycine, a key amino acid found in Glycine max, functions as an inhibitory neurotransmitter and plays a role in modulating inflammatory pathways, oxidative stress, and apoptosis. It also stimulates muscle protein synthesis and collagen formation. Soy isoflavones, another important component, act as phytoestrogens. They bind to estrogen receptors in the body, which can modulate lipid metabolism and vascular function. Oral absorption of glycine is efficient, while the bioavailability of isoflavones is influenced by the gut microbiota's metabolic activity. These mechanisms collectively contribute to the observed metabolic, cardiovascular, and anti-inflammatory effects of Glycine max.

Side effects

Glycine max and its components, particularly glycine, are generally considered safe at typical dietary and supplemental doses. However, high doses of glycine, specifically exceeding 500 mg/kg body weight, have been associated with potential renal, hepatic cytotoxicity, or neurotoxicity in animal models. It is important to note that these doses are significantly higher than those typically used in human supplementation. Soy isoflavones are generally well-tolerated, but individuals with a known allergy to soybean proteins may experience allergic reactions. There are no major drug interactions or contraindications that are well-documented for Glycine max. Nevertheless, caution is advised for individuals with soy allergies or those with hormone-sensitive conditions, and consultation with a healthcare provider is recommended in such cases. Overall, while generally safe, adherence to recommended dosages and awareness of potential allergic reactions are important.

Dosage

For metabolic effects, clinical studies have utilized glycine doses of 5 grams, administered three times daily. For lipid-lowering benefits, studies on soy protein typically involve an intake of approximately 25-50 grams per day. While there is no established maximum safe dose for Glycine max or its components, it is crucial to avoid extremely high doses of glycine due to potential toxicity observed in animal studies. The timing of intake relative to meals is generally not considered critical for efficacy. However, consistent daily intake is recommended to achieve and maintain the desired metabolic and cardiovascular benefits. It is always advisable to consult a healthcare professional for personalized dosage recommendations, especially for specific health conditions.

FAQs

Is glycine from Glycine max effective for diabetes?

Yes, some randomized controlled trials indicate that glycine supplementation can improve insulin sensitivity and reduce HbA1c levels in individuals with type 2 diabetes.

Are soy supplements safe for everyone?

Generally, soy supplements are safe. However, individuals with soy allergies or hormone-sensitive conditions should consult a healthcare provider before use.

Does glycine improve athletic performance?

Current human evidence is insufficient to confirm that glycine improves athletic performance, though some animal studies suggest potential benefits.

Research Sources

https://pmc.ncbi.nlm.nih.gov/articles/PMC10828290/ – This systematic review and included RCTs found that glycine improved insulin response and reduced HbA1c in type 2 diabetes patients. However, effects in metabolic syndrome were mixed, showing heterogeneity in populations and doses.
https://pmc.ncbi.nlm.nih.gov/articles/PMC11510825/ – This narrative review highlighted glycine's cytoprotective properties and its role in muscle repair. It noted a lack of rigorous human RCTs for ergogenic benefits and warned about potential toxicity at very high doses in animals.
https://www.fitoterapia.net/archivos/201809/wc500252713.pdf?1 – This systematic review of 17 studies concluded that soy isoflavones exhibit lipid-lowering and cardiovascular benefits, with an acceptable safety profile. It acknowledged study heterogeneity and variable outcomes.
https://www.jscholarpublishers.com/articles/JFN/Therapeutic-Effect-of.pdf – This RCT in diabetic rats demonstrated that soy protein reduced hyperlipidemia and improved cardiovascular markers. The study provides preclinical evidence, but extrapolation to humans is limited.
https://pubs.acs.org/doi/10.1021/acsfoodscitech.2c00380 – This systematic review and meta-analysis focused on human allergy studies, characterizing soybean allergens and confirming the presence of allergy risk, which is manageable. It primarily addressed allergenicity rather than efficacy.