Walnut: benefits, dosage, contraindications
Other name(s)
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Scientific name(s)
Juglans regia
Family or group:
Plants, Super Food
Active ingredients:
Vitamin E
Vitamin B9
Quercetin
Myricetin
Indications
Rating methodology
EFSA approval.
Hypercholesterolemia ✪✪✪✪✪
Clinical studies suggest that consuming nuts, integrated into a low-fat diet, may help reduce cholesterol levels. When these nuts replace other fat sources and account for up to 20% of the calories in a diet, there is a decrease in total cholesterol as well as lipoproteins. Furthermore, substituting nuts for other fats in a diet containing 30% fat seems to improve the HDL cholesterol (high-density lipoprotein, known as 'good' cholesterol) to total cholesterol ratio in patients with type 2 diabetes. Another study involved 100 type 2 diabetic and hyperlipidemic patients. They received 15 ml of walnut oil or a placebo daily for 90 days. The results showed a significant decrease in total cholesterol, triglycerides, and LDL, as well as a tendency to increase HDL in those consuming walnut oil. These findings are supported by a more recent study conducted on 45 adults at risk of cardiovascular disease. Participants followed three different diets for 6 weeks each: a diet including nuts, a diet with fatty acids matching those in nuts but without nuts, and a diet replacing the alpha-linolenic acid from nuts with oleic acid. The study showed that the nut-including diet significantly reduced central diastolic blood pressure and improved lipid profile. The authors conclude that cardiovascular benefits are observed with all diets rich in unsaturated fats, and that walnuts, as a complete substitution for saturated fats, offer additional advantages for cardiovascular health. These findings highlight the potential of nuts and oil in managing hypercholesterolemia, suggesting they could be a useful complement to a balanced diet for improving cardiovascular health.
Posologie
Oral: nuts
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 favourably influences plasma fatty acid profile in moderately hyperlipidaemic subjects.
Coronary diseases ✪✪✪✪✪
Epidemiological research has shown that people who increase their consumption of nuts in general might have a lower risk of coronary disease and death due to coronary events. However, there is no available evidence showing that nut consumption, in particular, reduces the risk of coronary heart disease. The EFSA has decided to permit a qualified health claim stating that consuming 30 g of nuts per day contributes to the improvement of blood vessel elasticity. The FDA has authorized a similar claim; within a diet low in saturated fats and cholesterol, nuts may reduce the risk of coronary heart disease.
Posologie
Oral: nuts
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 walnut leaf extract at 100 mg twice a day for 3 months decreases fasting blood glucose by 13% compared to placebo. However, other clinical research shows that taking walnut leaf extract at 100 mg once a day for one week, then twice a day for 7 weeks, has no effect on fasting blood glucose. Taking walnut leaf extract for a period of up to 3 months does not seem to improve glycosylated hemoglobin (HbA1c) or lipid levels in patients with type 2 diabetes.
Posologie
Oral: 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 are traditionally used in the symptomatic treatment of mild diarrhea, thanks to their anti-infectious and anti-diarrheal properties. The walnut is also recommended in cases of intestinal dysbiosis or imbalance of intestinal flora.
Posologie
Oral: 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 ✪✪✪✪✪
In relation to its hypoglycemic and hypocholesterolemic properties already presented, buds or leaves may help better control blood sugar levels in patients with metabolic syndrome.
Posologie
Oral: 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 acknowledges the traditional use of leaves for the relief of minor inflammatory skin conditions.
Posologie
Cutaneous, oral: leaf, buds
4 g
gemmotherapy, mother tincture, aqueous decoction
Perspiration ✪✪✪✪✪
For external use, the EMA suggests the use of leaves against mild superficial dermatological inflammations and excessive sweating of hands and feet.
Posologie
Cutaneous: leaf
lotion
Mycoses ✪✪✪✪✪
Thanks to its antifungal properties, the walnut is recommended in cases of intestinal mycoses.
Posologie
Oral: leaf, buds
4 g
gemmotherapy, mother tincture, aqueous decoction
Properties
Cardiovascular
Some clinical research suggests that walnut may reduce the risk of cardiovascular disease by lowering total cholesterol and low-density lipoprotein (LDL) cholesterol. In theory, other constituents such as fibers, vitamin E, and folates could contribute to the potential beneficial effect regarding cardiovascular disease risk. Clinical research also suggests that walnuts may improve endothelial function, which could be beneficial in preventing atherosclerosis. In addition to alpha-linolenic acid, walnuts contain significant amounts of arginine, an amino acid precursor to nitric oxide (NO), an endogenous vasodilator. Walnut leaf could have hypotensive, vasorelaxant, and smooth muscle-stimulating effects.
Usages associés
Hypoglycemic
Walnut leaves prove to be a valuable ally for glucose regulation in the blood, which is particularly interesting for people suffering from type 2 diabetes. They act through several well-defined mechanisms. One of these mechanisms involves influencing specific enzymes in our muscles and liver, including myocytic protein tyrosine phosphatase 1B and hepatic glucose-6-phosphatase. Their role is essential: they regulate glucose levels in the blood. By modulating the activity of these enzymes, walnut leaves effectively contribute to glucose management. The leaves promote the health of the Langerhans islets in the pancreas, a crucial area for insulin production. They stimulate the regeneration of these islets and increase the percentage of pancreatic b2-cells, thus enhancing the body's capacity to produce the necessary insulin to regulate blood glucose. Additionally, walnut leaves act on glucose absorption at the intestinal level by inhibiting the glucose transporter GLUT 2. This action limits the amount of glucose absorbed into the blood from the intestine, thereby contributing to better blood glucose regulation. Clinical studies have shown that in patients with type 2 diabetes on standard treatment, taking 200 mg of walnut leaves per day for three months led to a significant decrease in fasting glucose levels. It also reduced levels of HbA1c, a key indicator of diabetes control in the long term, 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 b2-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. Results comparable to those of aspirin have been obtained in the mouse paw acute edema model.
Usages associés
Antioxidant
The numerous flavonoids (quercetins, myricetins, kaempferol) present in walnut leaves possess antioxidant properties. In one study, tested walnut extracts had higher antioxidant activity than that observed with b1-tocopherol (vitamin E).
Hepato-protective
Walnut leaf extracts increased hepatic catalase and superoxide dismutase activities and reduced plasma alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase concentrations, in a carbon tetrachloride-induced hepatitis model in rats.
Digestive effect
Walnut leaves are traditionally used in the symptomatic treatment of mild diarrhea. These properties have been verified 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 molecules exhibit anti-inflammatory and antioxidant properties, and also have the ability to inhibit hydroelectrolytic secretions and motility at the intestinal level.
Usages associés
Antibacterial
Walnut leaf inhibits, in vitro, the growth of certain Gram-positive bacteria that can be responsible for foodborne intoxications (Bacillus cereus, Staphylococcus aureus, and bacteria of the Listeria genus) or oral pathologies (Streptococcus mutans and Actinomyces viscosus).
Usages associés
Antifungal
The inhibition of fungi responsible for skin and nail mycoses (Microsporum canis and Trichophyton violaceum) has been reported with results comparable to those of griseofulvin (the reference antifungal for mycoses).
Usages associés
Safety dosage
Adult from 18 years: 200 mg - 1500 mg (dry extract)
- Decoction at a rate of 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 the preparation of decoction for cutaneous use: 4-6 g of crushed plant material in 200 ml of boiling water. Apply as a soaked dressing on affected skin areas 2 to 4 times a day.
Adult from 18 years: 15 mL (oil)
Walnut oil is recommended as part of a balanced diet to support cardiovascular health.
Precautions
Pregnant woman: avoid
In the absence of data in pregnant and lactating women as well as in children (-18 years), the use of medicines containing this plant is not recommended as a precaution.
Nursing woman: avoid
In the absence of data in pregnant and lactating women as well as in children (-18 years), the use of medicines containing this plant is not recommended as a precaution.
Child up to 18 years: avoid
In the absence of data in pregnant and lactating women as well as in children (-18 years), the use of medicines containing this plant is not recommended as a precaution.
Constipation: avoid
Due to its anti-diarrheal property, it is not recommended to use walnut in cases of severe constipation.
