Hazelnuts have formed part of the human diet since prehistoric times, and rightly so as they are nutritious and delicious.
Moreover, they are incredibly versatile, making it easy to include in many different recipes. Hazelnuts are high in monounsaturated fat, fiber, potassium, iron, magnesium, phosphorus, copper, manganese, and vitamins E, B1, and B6. Additionally, they are a source of zinc, and vitamins K and B5. Due to their high monounsaturated fat content, they may help lower LDL (“bad”) cholesterol levels and lower your risk of heart disease.
Nutritional CompositionOne serving size of hazelnuts is considered to be around 30 grams, which is approximately 21 kernels. When looking at the nutritional composition of these tree nuts, you can see that they are an excellent addition to any diet. One serving of hazelnuts contains around 180 calories and 3 grams of fiber, which based on a 2,000 calories diet for general nutrition advice, is 11% of your daily fiber needs. Moreover, there are 4 grams of protein in one serving of hazelnuts. Monounsaturated fat accounts for 76% of all fat in one serving, while 12% come from polyunsaturated fats. This means that the fats found in hazelnuts are considered to be “healthy” fats.
Hazelnuts also provide various minerals and vitamins for those who consume them. Consuming just 30 grams of hazelnuts can result in 1.75 mg of manganese, which accounts for 80% of your daily value needed. Another mineral that is found in hazelnuts is copper, and there is 0.49 mg found in one serving, representing 25% of your daily value. When it comes to vitamins, there is 4.26 mg of vitamin E, meaning you can reach 30% of your daily value, while there is 0.16mg of vitamin B6, accounting for 10% of your daily need. All in all, it is not difficult to see why you might want to start including these tasty treats into your diet, if you haven’t done so already!
Heart HealthOne area of research that has been of focus of hazelnuts is the effect on heart health and blood lipids. This is in part because of the exceptionally high level of monounsaturated fatty acids that hazelnuts contain. In 2019, a study was published in the journal Nutrients where the researchers performed a systematic review and meta-analysis to see how hazelnut consumption affected blood lipids and body weight. In total, nine studies with 425 participants were included in the analysis. The hazelnut enriched diet intervention lasted between 28 and 84 days while participants consumed 29 to 69 grams of hazelnuts per day. Out of the nine studies, three randomized studies were analyzed further with a meta-analysis, which showed that those who consumed hazelnuts saw a significant reduction in low-density lipoprotein or LDL (“bad”) cholesterol, while total cholesterol had a marked downward trend as well. This study also revealed that high-density lipoprotein or HDL (“good”) cholesterol remained stable and there was no effect on body mass index (BMI).
The results showed that diets that have been enriched with hazelnuts are associated with lower LDL and total cholesterol levels, while HDL cholesterol and BMI remained unchanged. Since lower LDL and total cholesterol levels are associated with a reduced risk of cardiovascular disease, the authors concluded that hazelnut consumption could be beneficial for heart health.
Emerging EvidenceWhile there is plenty of research analyzing various health effects of mixed nuts, which includes hazelnuts, there are a limited number of studies that solely consider them. In a 2019 study, in the journal Oxidative Medicine and Cellular Longevity, researchers looked at how hazelnut consumption affected oxidative stress, inflammation gene expression, and weight parameters. In this prospective clinical trial, 24 participants were directed to consume 40 grams of hazelnuts per day for six weeks.
The results showed that there was no increase in body weight for the participants who consumed hazelnuts. Previous research has shown that tree nuts have satiating properties which can make an individual feel full for longer, and this is a possible reason given by the authors regarding no weight gain among the participants. The authors also hypothesize that according to emerging evidences, hazelnut antioxidant capacity and antiinflammatory properties could be another reason for why participants did not gain weight.
1. Perna, S., Giacosa, A., Bonitta, G., Bologna, C., Isu, A., Guido, D., & Rondanelli, M. (2016) Effects of hazelnut consumption on blood lipids and body weight: a systematic review and Bayesian meta-analysis. Nutrients, 8(12).
2. Hazelnuts. Nuthealth.org. (2021, January 14). Retrieved January 26, 2022, from https://nuthealth.org/nut-facts/hazelnuts/
3. U.S. Food and Drug Administration (FDA): Qualified Health Claims.
4. Di Renzo, L., Cioccoloni, G., Bernardini, S., Abenavoli, L., Aiello, V., Marchetti, M., ... & Gratteri, S. (2019). A Hazelnut Enriched Diet Modulates Oxidative Stress and Inflammation Gene Expression without Weight Gain. Oxidative medicine and cellular longevity, 2019.