Walnut: benefits, dosage, contraindications
Scientific name(s)
Juglans regia
Family or group:
Plants, Superfood
Active ingredients:
Vitamin E
Vitamin B9
Quercetin
Myricetin
Indications
Scoring methodology
EFSA approval.
Hypercholesterolemia ✪✪✪✪✪
Clinical studies suggest that consuming nuts, incorporated into a low-fat diet, can help lower cholesterol levels. When these nuts replace other sources of fat and account for up to 20% of a diet's calories, a reduction in total cholesterol as well as lipoproteins is observed. Furthermore, when nuts are substituted for other fats in a diet containing 30% fat, this appears to improve the ratio of HDL cholesterol (high-density lipoprotein, known as the 'good' cholesterol) to total cholesterol in patients with type 2 diabetes. Another study involved 100 type 2 diabetic, hyperlipidemic patients. They received 15 ml of walnut oil daily or a placebo for 90 days. The results showed a significant decrease in total cholesterol, triglycerides, and LDL, as well as a trend toward increased HDL among those who consumed walnut oil. These results are corroborated by another more recent study conducted on 45 adults at risk for cardiovascular disease. Participants followed three different diets for six weeks each: a diet including nuts, a diet with fatty acids matching those of nuts but without the nuts, and a diet replacing the nuts' alpha-linolenic acid with oleic acid. The study showed that the diet including nuts significantly reduced central diastolic blood pressure and improved the lipid profile. The authors conclude that cardiovascular benefits are observed with all diets rich in unsaturated fats, and that nuts, as a full replacement for saturated fats, provide additional benefits for cardiovascular health. These findings highlight the potential of nuts and oil in managing hypercholesterolemia, suggesting that they could be a useful complement to a balanced diet to improve cardiovascular health.
Posologie
Oral: walnuts
15 mL
oil, dry extract
Replacing Saturated Fat With Walnuts or Vegetable Oils Improves Central Blood Pressure and Serum Lipids in Adults at Risk for Cardiovascular Disease: A Randomized Controlled-Feeding Trial
Effects of walnuts on serum lipid levels and blood pressure in normal men.
Effects of walnut oil on lipid profiles in hyperlipidemic type 2 diabetic patients: a randomized, double-blind, placebo-controlled trial
Including walnuts in a low-fat/modified-fat diet improves HDL cholesterol-to-total cholesterol ratios in patients with type 2 diabetes
A diet rich in walnuts favorably influences plasma fatty acid profile in moderately hyperlipidemic subjects.
Coronary heart disease ✪✪✪✪✪
Epidemiological research has shown that people who increase their consumption of tree nuts in general may have a lower risk of coronary heart disease and of death due to coronary events. However, there is no available evidence showing that consumption of walnuts, specifically, reduces the risk of coronary heart disease. EFSA has decided to authorize a qualified health claim indicating that consumption of 30 g of walnuts per day contributes to the improvement of vascular elasticity The FDA has authorized a similar claim; as part of a diet low in saturated fat and cholesterol, walnuts may reduce the risk of coronary heart disease.
Posologie
Oral: walnuts
30 g
oil, dry extract
Nut consumption and risk of coronary heart disease: a review of epidemiologic evidence.
Effect of nut consumption on vascular endothelial function: A systematic review and meta-analysis of randomized controlled trials
Effects of walnuts on serum lipid levels and blood pressure in normal men.
Type 2 diabetes ✪✪✪✪✪
Some clinical research shows that taking a walnut leaf extract at 100 mg twice daily for 3 months reduces fasting blood glucose by 13% compared with placebo. However, other clinical research shows that taking a walnut leaf extract at 100 mg once daily for one week, then twice daily for 7 weeks, has no effect on fasting blood glucose. Taking a walnut leaf extract for a period of up to 3 months does not appear to improve glycated hemoglobin (HbA1c) or lipid levels in patients with type 2 diabetes.
Posologie
By mouth: leaf, buds
200 mg
3 months
gemmotherapy, mother tincture, dry extract
Antihypertriglyceridemic effect of walnut oil
Effects of Juglans regia L. leaf extract on hyperglycemia and lipid profiles in type two diabetic patients: a randomized double-blind, placebo-controlled clinical trial.
Effects of a hydroalcoholic extract of Juglans regia (walnut) leaves on blood glucose and major cardiovascular risk factors in type 2 diabetic patients: a double-blind, placebo-controlled clinical trial
Anti-hyperglycemic effect of aqueous extract of Juglans regia L. leaf (walnut leaf) on type 2 diabetic patients: A randomized controlled trial
Diarrhea ✪✪✪✪✪
Walnut leaves have traditionally been used in the symptomatic treatment of mild diarrhea, due to their anti-infective and anti-diarrheal properties.nnThe walnut is also recommended in cases of intestinal dysbiosis, or imbalance of the intestinal flora.nn
Posologie
Oral use: leaf, buds
4 g
gemmotherapy, mother tincture, aqueous decoction
Bruneton J. Pharmacognosy. Phytochemistry. Medicinal Plants 1999.
Walnut Consumption Alters the Gastrointestinal Microbiota, Microbially Derived Secondary Bile Acids, and Health Markers in Healthy Adults: A Randomized Controlled Trial
Metabolic syndrome ✪✪✪✪✪
Due to its previously described hypoglycemic and hypocholesterolemic properties, the buds or leaves may help better control blood glucose in patients with metabolic syndrome.nn
Posologie
Oral use: leaf, buds
200 mg
gemmotherapy, mother tincture, dry extract
Antihypertriglyceridemic effect of walnut oil
Effects of Juglans regia L. leaf extract on hyperglycemia and lipid profiles in type two diabetic patients: a randomized double-blind, placebo-controlled clinical trial.
Effects of a hydroalcoholic extract of Juglans regia (walnut) leaves on blood glucose and major cardiovascular risk factors in type 2 diabetic patients: a double-blind, placebo-controlled clinical trial
Dermatoses ✪✪✪✪✪
The EMA recognizes the traditional use of the leaves for the relief of minor inflammatory skin conditions.nn
Posologie
For topical and oral use: leaf, buds
4 g
gemmotherapy, mother tincture, aqueous decoction
Sweating ✪✪✪✪✪
In external use, the EMA recommends using the leaves for mild superficial dermatological inflammations and excessive sweating of the hands and feet.
Posologie
Topical use: leaf
lotion
Fungal infections ✪✪✪✪✪
Thanks to its antifungal properties, walnut is recommended in cases of intestinal fungal infections.
Posologie
Oral use: leaf, buds
4 g
gemmotherapy, mother tincture, aqueous decoction
Properties
Cardiovascular
Some clinical research suggests that walnuts may reduce the risk of cardiovascular disease by lowering total cholesterol and low-density lipoprotein (LDL) cholesterol. In theory, other constituents such as fiber, vitamin E and folate could contribute to the potential beneficial effect on cardiovascular disease risk. nnClinical research also suggests that walnuts may improve endothelial function, which could be beneficial in the prevention of atherosclerosis. In addition to alpha-linolenic acid, walnuts contain significant amounts of arginine, an amino acid precursor of nitric oxide (NO), an endogenous vasodilator. nnWalnut leaf may have hypotensive, vasorelaxant and smooth muscle-stimulating effects.nn
Usages associés
Hypoglycemic
Walnut leaves have proven to be a valuable ally in regulating blood glucose, which is particularly relevant for people with type 2 diabetes. They act through several well-defined mechanisms. One of these mechanisms involves influencing specific enzymes in our muscles and liver, notably myocytic protein tyrosine phosphatase 1B and hepatic glucose-6-phosphatase. Their role is essential: they regulate blood glucose levels. By modulating the activity of these enzymes, walnut leaves contribute effectively to glucose management. The leaves promote the health of the pancreatic islets of Langerhans, a crucial area for insulin production. They stimulate the regeneration of these islets and increase the percentage of pancreatic β-cells, thereby strengthening the body’s capacity to produce the insulin necessary to regulate blood glucose. Furthermore, walnut leaves act on intestinal glucose absorption by inhibiting the glucose transporter GLUT2. This action limits the amount of glucose absorbed into the bloodstream from the intestine, thereby contributing to better blood glucose regulation. Clinical studies have shown that in patients with type 2 diabetes who were receiving standard treatment, taking 200 mg of walnut leaves per day for three months led to a significant decrease in fasting glucose. It also reduced HbA1c levels, a key marker of long-term diabetes control, as well as total cholesterol and triglyceride levels.
Usages associés
Comparison of the effects of fresh leaf and peel extracts of walnut (Juglans regia L.) on blood glucose and β-cells of streptozotocin-induced diabetic rats
Anti-hyperglycemic effect of aqueous extract of Juglans regia L. leaf (walnut leaf) on type 2 diabetic patients: A randomized controlled trial
Inhibition of the intestinal glucose transporter GLUT2 by flavonoids
Effect of ethanolic extract of Juglans regia L. on blood sugar in diabetes-induced rats
Anti-inflammatory
Quercetin in walnut leaves is anti-inflammatory. Quercetin inhibits the production and activity of leukotrienes and prostaglandins and the release of histamine. nnResults comparable to those of aspirin were obtained in the acute mouse paw edema model.nn
Usages associés
Antioxidant
The many flavonoids (quercetins, myricetins, kaempferol) present in walnut leaves have antioxidant properties. In one study, the tested walnut extracts showed antioxidant activity greater than that observed with α-tocopherol (vitamin E).nn
Hepatoprotective
Walnut leaf extracts led to increased hepatic catalase and superoxide dismutase activities and to a reduction in plasma concentrations of alanine aminotransferase, aspartate aminotransferase and alkaline phosphatase, in a model of hepatitis induced by intraperitoneal injection of carbon tetrachloride in rats.nn
Digestive effect
Walnut leaves have traditionally been used in the symptomatic treatment of mild diarrhea. These properties have been confirmed in vivo. They have been attributed to the presence of hydroxycinnamic acids and flavonoids (mainly derivatives of quercetin, myricetin, kaempferol, and taxifolin). Some of these compounds show anti-inflammatory and antioxidant properties and also have the ability to inhibit hydroelectrolytic secretions and intestinal motility.
Usages associés
Antibacterial
The walnut leaf inhibits, in vitro, the growth of certain Gram-positive bacteria that can cause foodborne poisoning (Bacillus cereus, Staphylococcus aureus, and bacteria of the genus Listeria) or oral diseases (Streptococcus mutans and Actinomyces viscosus).
Usages associés
Antifungal
The inhibition of fungi responsible for mycoses of the skin and its appendages (Microsporum canis and Trichophyton violaceum) has been reported, with results comparable to those of griseofulvin (the reference antifungal for mycoses).
Usages associés
Safe dosage
Adults 18 years and older: 200 mg - 1500 mg (dry extract)
- Decoction at 1.5 g per cup 1 to 3 times a day - In gemmotherapy: 1D, 40 to 60 drops per day. - In mother tincture or fluid extract: 30 to 40 drops in a little water (MT) morning and evening - Crushed plant material for preparing a decoction for topical use: 4-6 g of crushed plant material in 200 ml boiling water. Apply as an impregnated dressing to the affected areas of the skin 2 to 4 times a day.
Adults 18 years and older: 15 mL (oil)
Walnut oil is recommended as part of a balanced diet to support cardiovascular health.
Precautions
Pregnant women: avoid
In the absence of data for pregnant and breastfeeding women and for children (under 18 years), the use of medicinal products containing this plant is not recommended as a precautionary measure.
Breastfeeding women: avoid
In the absence of data for pregnant and breastfeeding women and for children (under 18 years), the use of medicinal products containing this plant is not recommended as a precautionary measure.
Children up to 18 years: avoid
In the absence of data in pregnant and breastfeeding women as well as in children (under 18 years old), the use of medications containing this plant is not recommended as a precautionary measure.
Constipation: avoid
Because of its anti-diarrheal properties, the use of walnut is not recommended in cases of severe constipation.
