Diet is considered an important modifiable lifestyle factor capable of slowing early cognitive changes in healthy older adults. Including nuts in your diet has been extensively studied as a strategy for maintaining brain health throughout the lifespan.
Recently, a review systematically searched all relevant articles from inception to April 2020. Eligible articles were assessed for adults aged 18 years ≥ the effects or associations of nuts such as almonds, hazelnuts, macadamia nuts, pistachios, walnuts, pecans, pine nuts, Brazil nuts, cashews, or peanuts on cognitive outcomes through interventional or observational research methods. Of the 2374 articles screened, 22 studies involving 43,793 participants met the inclusion criteria and were used in this review analysis.
The studies explored cognitive outcomes including immediate versus delayed memory, attention, processing speed, executive function, visuospatial ability, and risk of mild cognitive impairment. Studies targeting groups at high risk of cognitive decline tended to find more positive outcomes. In addition, studies that specifically examined the association between walnut consumption and cognitive performance found more consistent conclusions: of six studies (including two randomised controlled trials), only one found no positive association.
In our daily diet, nuts are favored for their rich nutritional value and unique flavor, which not only bring enjoyment to our taste buds, but also contribute a lot to our health. Let's explore the natural treasures of six common nuts – almonds, hazelnuts, macadamia nuts, pistachios, walnuts, pecans, pine nuts, Brazil nuts, cashews and peanuts.
杏仁（Almond）
Almonds are known for their delicate taste and rich nutrients, containing high-quality protein, fiber, vitamin E, magnesium and monounsaturated fatty acids that support heart health and intestinal motility, while the antioxidant properties of vitamin E are also beneficial for the skin.
榛子（Hazelnut）
Hazelnuts are rich in healthy monounsaturated fats, as well as vitamins E, B complex, minerals such as potassium, calcium, and magnesium. Their antioxidant properties help reduce the risk of cardiovascular disease, and the fiber in hazelnuts is also helpful in maintaining blood sugar balance.
(Macadamia)
Macadamia nuts are known for their creamy texture and abundance of monounsaturated fatty acids, which help lower bad cholesterol levels. It is also a good source of vitamins B1, B6, minerals such as magnesium, copper, and zinc, which are essential for nerve health and energy metabolism.
开心果（Pistachio）
Pistachios are not only attractive in color, but they are also nutritious, containing protein, fiber, vitamin B6, potassium, and antioxidants such as lutein and zeaxanthin, which are beneficial for eye health. They can also help with weight control, as their fiber and protein can increase feelings of fullness.
核桃（Walnut）
Walnuts are known as the "food of the brain" because of their brain-like shape, and are rich in omega-3 fatty acids α-linolenic acid, which are especially beneficial for brain health. In addition, walnuts contain antioxidants such as ellagic acid, which helps fight inflammation, and are rich in phytosterols, which contribute to heart health.
山胡桃(Pecan)
Hickory is an excellent source of antioxidants, especially its high levels of vitamin E and the trace element selenium, which are very effective in fighting free radical damage. They are also rich in heart-healthy monounsaturated fats and fiber, which help maintain cardiovascular health.
松子（Pine Nut）
Pine nuts are small and delicate, rich in protein, healthy fats, vitamin K and vitamin E, and especially rich in copper, which is essential for blood health and antioxidant defenses. They have a unique taste and are often used in cooking to add flavor.
巴西坚果（Brazil Nut）
Brazil nuts are known for their extremely high content of selenium, a powerful antioxidant mineral that is essential for immune system function. They also contain healthy fats, protein, and vitamin E, which are also beneficial for maintaining male reproductive health when consumed in moderation.
腰果（Cashew）
Cashews are a good source of iron, zinc, and magnesium, minerals that are essential for hemoglobin formation, immune system support, and muscle relaxation. They are high in monounsaturated fats and proteins, which contribute to cardiovascular health and provide long-lasting energy.
花生（Peanut）
Although technically leguminous rather than a nut, peanuts are nutritionally similar to nuts and are rich in protein, fiber, vitamin E, B vitamins, and heart-healthy monounsaturated fats. Peanuts also contain an antioxidant called resveratrol, which is beneficial for preventing cardiovascular disease.
How many nuts to eat per day
Recommendations for the appropriate amount of nuts per day vary from source to source, but most recommendations focus on around 25-35 grams per day. This amount is about the equivalent of a small handful of nuts. For example, according to some health guidelines and studies, the recommended daily intake of nuts for adults is roughly as follows:
While nuts are high in healthy fats, protein, fiber, vitamins, and minerals that are beneficial for heart health and overall well-being, they are higher in calorie density. Therefore, moderate consumption is key, and excessive intake may lead to excess calories and affect weight management. When choosing nuts, it is preferred to choose unprocessed, unsalted or low-salt versions to avoid additional sodium intake and possible additives.
Given individual differences, people with specific health conditions, such as obesity, poor gastrointestinal function, or chronic medical conditions, should adjust their nut intake based on their own situation and the advice of a doctor or dietitian. In conclusion, incorporating nuts into your daily diet in moderation and variety is the best way to enjoy their health benefits.
综述文献参考——Theodore LE, Kellow NJ, McNeil EA, Close EO, Coad EG, Cardoso BR. Nut Consumption for Cognitive Performance: A Systematic Review. Adv Nutr. 2021 Jun 1; 12(3):777-792. doi: 10.1093/advances/nmaa153. PMID: 33330927; PMCID: PMC8166568.