Walnuts, known for their distinctive brain-like appearance, are more than just a key ingredient in desserts and snacks. These nutrient-rich nuts, packed with essential fatty acids and omega-3s, offer a multitude of health benefits. From improving heart health and brain function to boosting male fertility and regulating sleep, walnuts are a powerhouse of nutrition. This blog will explore their diverse benefits and how they can be a valuable addition to a healthy diet.
What are Walnuts?
Walnuts are edible seeds from the trees of Juglans genus. They are round, single-seeded fruits of the walnut tree. The fruit and seed of walnut are enclosed in a thick, inedible husk. The shell of the fruit that encloses the kernel is hard and two-halved.
Walnuts have a delicious taste and crunchy texture, which is why they are used in many desserts and baked goods such as cookies, cakes, granola, cereals, energy bars, and the ever-popular banana walnut bread. Ground walnuts and walnut flour are also used for baking.
The nuts have always been considered as ‘brain food’ perhaps because the surface structure of the walnut has a wrinkled appearance, like that of the brain. Due to this reason, they have been considered as a symbol of intelligence, leading to the belief by some that they actually increase one’s intellect!
| Serving Size : | |
|---|---|
| Nutrient | Value |
| Water [g] | 4.07 |
| Energy | 654 |
| Energy [kJ] | 2738 |
| Protein [g] | 15.23 |
| Total lipid (fat) [g] | 65.21 |
| Ash [g] | 1.78 |
| Carbohydrate, by difference [g] | 13.71 |
| Fiber, total dietary [g] | 6.7 |
| Sugars, total including NLEA [g] | 2.61 |
| Sucrose [g] | 2.43 |
| Glucose (dextrose) [g] | 0.08 |
| Fructose [g] | 0.09 |
| Starch [g] | 0.06 |
| Calcium, Ca [mg] | 98 |
| Iron, Fe [mg] | 2.91 |
| Magnesium, Mg [mg] | 158 |
| Phosphorus, P [mg] | 346 |
| Potassium, K [mg] | 441 |
| Sodium, Na [mg] | 2 |
| Zinc, Zn [mg] | 3.09 |
| Copper, Cu [mg] | 1.59 |
| Manganese, Mn [mg] | 3.41 |
| Selenium, Se [µg] | 4.9 |
| Vitamin C, total ascorbic acid [mg] | 1.3 |
| Thiamin [mg] | 0.34 |
| Riboflavin [mg] | 0.15 |
| Niacin [mg] | 1.13 |
| Pantothenic acid [mg] | 0.57 |
| Vitamin B-6 [mg] | 0.54 |
| Folate, total [µg] | 98 |
| Folate, food [µg] | 98 |
| Folate, DFE [µg] | 98 |
| Choline, total [mg] | 39.2 |
| Betaine [mg] | 0.3 |
| Vitamin A, RAE [µg] | 1 |
| Carotene, beta [µg] | 12 |
| Vitamin A, IU [IU] | 20 |
| Lutein + zeaxanthin [µg] | 9 |
| Vitamin E (alpha-tocopherol) [mg] | 0.7 |
| Tocopherol, beta [mg] | 0.15 |
| Tocopherol, gamma [mg] | 20.83 |
| Tocopherol, delta [mg] | 1.89 |
| Vitamin K (phylloquinone) [µg] | 2.7 |
| Fatty acids, total saturated [g] | 6.13 |
| 16:0 [g] | 4.4 |
| 18:0 [g] | 1.66 |
| 20:0 [g] | 0.06 |
| Fatty acids, total monounsaturated [g] | 8.93 |
| 18:1 [g] | 8.8 |
| 20:1 [g] | 0.13 |
| Fatty acids, total polyunsaturated [g] | 47.17 |
| 18:2 [g] | 38.09 |
| 18:3 [g] | 9.08 |
| Campesterol [mg] | 5 |
| Beta-sitosterol [mg] | 87 |
| Tryptophan [g] | 0.17 |
| Threonine [g] | 0.6 |
| Isoleucine [g] | 0.63 |
| Leucine [g] | 1.17 |
| Lysine [g] | 0.42 |
| Methionine [g] | 0.24 |
| Cystine [g] | 0.21 |
| Phenylalanine [g] | 0.71 |
| Tyrosine [g] | 0.41 |
| Valine [g] | 0.75 |
| Arginine [g] | 2.28 |
| Histidine [g] | 0.39 |
| Alanine [g] | 0.7 |
| Aspartic acid [g] | 1.83 |
| Glutamic acid [g] | 2.82 |
| Glycine [g] | 0.82 |
| Proline [g] | 0.71 |
| Serine [g] | 0.93 |
| Sources include : USDA [1] | |
Nutritional Value of Walnuts
According to the USDA Food Data Central, walnuts are a rich source of vitamin C, B vitamins (vitamin B6, thiamin, riboflavin, niacin, pantothenic acid, and folate), vitamin E, as well as minerals such as calcium, iron, magnesium, potassium, sodium, and zinc. [2]
Walnuts are 65 percent fat by weight and 15 percent protein. They are richer than most nuts in polyunsaturated fats (often considered the “good” fats) and have a relatively high amount of omega-3 fatty acid called alpha-linolenic acid (ALA). Walnuts are also particularly rich in an omega-6 fatty acid called linoleic acid.
Walnuts contain other essential nutrients such as beta-carotene, lutein, and zeaxanthin, as well as phytosterols. They are a good source of dietary fiber and antioxidants (ellagic acid, catechin, melatonin, and phytic acid). All of these beneficial nutrients contribute to walnuts being thought of by many as ‘power food’.
Health Benefits of Walnuts
Let’s find out some of the major health benefits of walnuts.
Improves Heart Health
Research in Metabolism showed that walnuts significantly lower LDL (bad) cholesterol and increase HDL (good) cholesterol. [3]
Extensive research over two decades confirms walnuts’ ability to decrease LDL cholesterol by 9-16% and diastolic blood pressure by 2-3 mm Hg. They also improve endothelial function and reduce oxidative stress, underlining their importance in a heart-healthy diet. [4]
These studies collectively advocate for including walnuts in daily diets to bolster cardiovascular health.
Helps in Managing Weight
Walnuts have been found to increase satiety, aiding in weight management. A study from Harvard Medical School showed that people consuming walnut shakes felt fuller compared to those who had placebo shakes, although it involved a small sample size. [5]
Another study revealed that a walnut-enriched diet can lead to weight loss similar to a standard reduced-energy diet, with added benefits like improved lipid profiles and lower systolic blood pressure. [6]
Loose walnuts on a table Photo Credit: Shutterstock
Boosts Bone Health
A study highlights the role of walnuts in supporting bone and endothelial cell function, suggesting their anti-atherogenic potential and osteoblastic activity, partly due to their ellagic acid component. This indicates that a walnut-enriched diet could contribute to both heart health and reduced bone loss. More research is required to support this claim. [7]
Improves Brain Health
Walnut oil, rich in omega-3 fatty acids, enhances memory and focus, as reported in the Journal of Nutrition, Health, and Aging. These fatty acids, along with iodine and selenium, are crucial for optimal brain function and are known to alleviate symptoms of cognitive disorders. [8]
Contains Antioxidant Power
Walnuts, ranking second in antioxidant-rich foods just behind blackberries, boast unique antioxidants like quinone juglone, tellimagrandin, and flavonol morin, which have potent free-radical scavenging abilities and can help prevent liver damage due to chemicals. [9]
Their high antioxidant content aligns with research linking diets rich in fruits, vegetables, and nuts with lower chronic disease risks, with walnuts particularly high in total antioxidants, especially in their pellicles. [10]
Additionally, walnuts, rich in polyunsaturated fatty acids and polyphenols, may positively impact the gut microbiome and exhibit anti-inflammatory properties, offering overall health benefits. [11]
Improves Metabolism
Walnut, along with EFAs, provides minerals like manganese, copper, potassium, calcium, iron, magnesium, zinc, and selenium to the body. These minerals help contribute to metabolic activities like growth and development, sperm generation, digestion, and nucleic acid synthesis. [12]
Helps in Controlling Diabetes
Including walnuts in your diet may be beneficial for those managing diabetes, as they are rich in polyunsaturated and monounsaturated fats. This composition is linked to a reduced risk of developing type-II diabetes, though it’s important to consume them in moderation. [13]
A study focusing on adults at risk for diabetes showed that daily walnut consumption for six months improved diet quality. However, it didn’t significantly change fasting blood glucose, HDL cholesterol, or blood pressure, indicating the need for controlled caloric intake alongside walnut consumption. [14]
Additionally, the Nurses’ Health Study, spanning from 1998 to 2009, found that higher walnut intake was associated with a lower risk of type 2 diabetes in women. This association remained significant even after adjusting for body mass index (BMI), highlighting the protective effect of regular walnut consumption. [15]
Cleanses Digestive System
Walnuts, a nutritional powerhouse, play a significant role in cleansing the digestive tract and facilitating detoxification. They assist in the removal of toxins and waste and even alleviate constipation. Lauri Byerley, an associate professor at Louisiana State University, found that daily walnut consumption boosts beneficial gut bacteria like Lactobacillus, Ruminococcus, and Roseburia, enhancing overall gut health as per a study on rats. [16]
Another study involving 194 healthy individuals revealed that an eight-week regimen of eating 43 grams of walnuts daily significantly altered the gut microbiome. This change favored probiotic and butyric acid-producing species, beneficial for gut health. This study also noted that these changes had little dependence on dietary adjustments made to accommodate the extra walnut intake. [17]
Furthermore, walnut consumption has been linked to increased levels of gut bacteria associated with butyrate production, reducing proinflammatory secondary bile acids and LDL cholesterol, thus contributing to their beneficial health effects. [18]
Improves Male Fertility
A study from the Fielding School of Public Health, University of California, highlights how walnuts positively affect male fertility. Specifically, consuming walnuts improves sperm quality, quantity, vitality, and motility. [19]
In a randomized control trial involving 75 participants with male factor infertility, adding 42 grams of walnuts daily to their diet for three months resulted in increased sperm motility and concentration. This contrasted with a group taking a daily nutritional supplement for reproductive health, which did not show significant changes. The walnut group also demonstrated improved sperm morphology, and preliminary data suggested a higher frequency of pregnancy in this group, although not statistically significant. [20]
Helps Regulate Sleep
Walnuts are a natural source of melatonin, the hormone responsible for inducing and regulating sleep. A study published in the 2005 issue of the journal Nutrition revealed that laboratory rats fed walnuts had higher blood melatonin concentrations compared to those on a controlled diet. [21]
Additionally, research underscores the role of dietary choices, including functional foods like walnuts, in preventing insomnia and promoting sleep. These foods are rich in sleep-promoting components such as tryptophan, GABA, melatonin, and others, highlighting the connection between diet and sleep quality. [22]
Helps With Anxiety
Walnuts, rich in omega-3 fatty acids, have been linked to mood improvements. A 2016 study in the Nutrients Journal showed that healthy males experienced a significant mood enhancement after walnut consumption. [23]
Additionally, a study focusing on university students revealed that walnut consumption could mitigate the adverse effects of academic stress on mental health and improve gut microbial diversity, particularly in females. [24]
Side Effects
On average, seven to nine walnuts per serving are considered safe for consumption. However, if you eat nuts in excess, there are some side effects you may experience, as follows:
- Allergy: Over-consumption may result in a range of allergic reactions from minor to lethal.
- Digestive issues: Excess intake of walnuts may cause nausea, stomach pain, diarrhea, bloating, and more.
- Weight gain: Although it is a source of good fats, taking too much of this nut can make your weight rise like nuts!
- Pregnancy and lactation: Expecting and nursing women are advised to consume in prescribed amounts only. If you desire to increase its dosage, consult your doctor.
Quick Serving Tips
Walnuts can be integrated into your diet to gain from all the associated health benefits. A few ways to add them to your meal are as follows:
