By Dr. Mercola
If you’re in the mood for a snack that’s as healthy for your brain as it is delicious, look no further than blueberries, a powerhouse of nutrition all wrapped up in a perfect bite-sized package. A much-cited Harvard study pointed out back in 2012 that higher intake of flavonoids, beneficial phytonutrients from plants — especially those from berries — reduced rates of cognitive decline in older adults.1
The berry intake delayed cognitive aging by up to 2.5 years, but the study participants consumed large amounts (up to six cups) of berries daily. A more recent study, this one published in the European Journal of Nutrition in 2018, yielded equally impressive results but using “easily achievable quantities of berries.”
In fact, when participants between the ages of 60 and 75 years consumed freeze-dried blueberry in an amount equivalent to 1 cup of fresh blueberries (24 grams (g)) daily, they experienced improved cognition after just 90 days.2
Children may benefit, too. When kids aged 7 to 10 years consumed blueberry drinks with either 15 or 30 g of freeze-dried wild blueberry powder, cognitive performance improved in a matter of hours.3 In this case, the more blueberries the better, and the best performance scores came following consumption of the 30-g portion.
Brain Benefits of Blueberries
Blueberries are rich in anthocyanins, flavonoids found in fruits with blue, red or dark purple hues, as well as other beneficial phytochemicals including caffeic acid, catechin, quercetin, kaempferol and tannin. These phytochemicals have known antioxidative, anti-inflammatory, antiviral and antiproliferative properties, and are thought to play a beneficial role in brain aging and neurodegenerative disorders. According to a study in Neural Regeneration Research:4
“Recent clinical research has demonstrated that berry fruits can prevent age-related neurodegenerative diseases and improve motor and cognitive functions. The berry fruits are also capable of modulating signaling pathways involved in inflammation, cell survival, neurotransmission and enhancing neuroplasticity.”
Even in older adults with cognitive impairment, consuming blueberries for 24 weeks led to fewer cognitive symptoms and improved memory discrimination, which is indicative of improved cognition.5 In short, your brain measurably benefits from the anthocyanins in blueberries.
Separate research similarly revealed that when older adults consumed blueberry concentrate that provided 387 milligrams (mg) of anthocyanidins for 12 weeks, they enjoyed improvements in working memory and enhanced task-related brain activation. “Supplementation with an anthocyanin-rich blueberry concentrate improved brain perfusion and activation in brain areas associated with cognitive function in healthy older adults,” the researchers noted.6
Blueberries in the Morning May Improve Concentration Until Afternoon
If you’re looking for a healthy breakfast, a blueberry smoothie might fit the bill, as research presented at the British Science Festival in Surrey University, Guildford, revealed that people who drank a blueberry smoothie in the morning performed better on mental tasks five hours later than did people who drank smoothies without blueberries.
The blueberry smoothies may have given participants’ brains a boost in flow of blood and oxygen, such that memory and concentration improved. By afternoon, people who did not have blueberries had declines in mental performance by up to 20 percent while the blueberry group was still going strong.7 It’s thought that blueberries and other flavonoid-rich foods may activate an enzyme called enos, which improves blood flow and oxygen to the brain.
Similar results were achieved in a study of 8- to 10-year-old children who consumed either a flavonoid-rich blueberry drink or a placebo beverage. Two hours after consumption, they then completed five cognitive tests. Children who consumed the blueberry drink had significant improvements in the delayed recall of a previously learned list of words, suggesting it may help school-age children with memory.8
Are Fermented Blueberries Best of All?
Fermented blueberry juice, although far less-known than the fresh berries, is a beverage worth looking into, as its benefits may even exceed those of the whole berries. This is because the fermentation process may help to preserve some of the beneficial phenolic compounds in berries that could otherwise become oxidized by processing or storage.
For instance, a study published in the Journal of Agricultural and Food Chemistry involving lab mice with amnesia suggests blueberry vinegar, which is produced by fermenting fresh blueberries, effectively improves short-term memory.9
The mice with amnesia were given either 120 mg per kilogram (kg) of blueberry vinegar or 120 mg per kg of blueberry extract every day for a week.
Mice given blueberry vinegar had a reduction in the breakdown of acetylcholine in their brains, which is significant because people with Alzheimer's disease generally have low levels of acetylcholine and blocking acetylcholine receptors is known to disrupt learning and memory. An increase in brain-derived neurotrophic factor (BDNF), a protein known for its role in nerve cell growth and maintenance, was also noted.
As demonstrated in the video below, you can easily make blueberry vinegar at home using just three ingredients: 1 cup of fresh blueberries, 2 cups of vinegar and sweetener equivalent to 2 tablespoons sugar. For the best results, be sure to use organic ingredients. Blueberry vinegar can be used as a salad dressing or marinade, especially for fish.
What Else Are Blueberries Good For?
Blueberries are native to North America and were valued by Native Americans for medicinal purposes as well as for fabric dye. In addition to flavonoids, they’re a rich source of vitamins C and K, manganese and dietary fiber. While perhaps best known for their role in boosting brain health, blueberries are also good for your heart.
Women who ate the most blueberries (and strawberries) were 34 percent less likely to have a heart attack over an 18-year study period, according to a Harvard study.10 "The people with heart benefits had three or more servings of a half a cup of blueberries or strawberries each week,” the study’s author, Eric Rimm, professor in Harvard’s departments of epidemiology and nutrition, said in a news release.11
The findings were again credited to anthocyanins, which are known to lower blood pressure and make blood vessels more elastic. Other research has shown these antioxidants to protect against heart disease by reducing oxidative stress and inflammation, while enhancing capillary strength and inhibiting platelet formation.12
Blueberries May Benefit Type 2 Diabetes
Blueberries may also be beneficial for prevention of Type 2 diabetes. According to the journal Antioxidants, “Epidemiological evidence indicates that incorporating blueberries into the diet may lower the risk of developing Type 2 diabetes (T2DM). These findings are supported by preclinical and clinical studies that have shown improvements in insulin resistance (i.e., increased insulin sensitivity) after obese and insulin-resistant rodents or humans consumed blueberries.”13
Fermented blueberries may also be particularly beneficial for Type 2 diabetes. Research featured in the International Journal of Obesity made use of a "biotransformed" blueberry juice fermented using Serratia vaccinii, a bacterium found on the fruit's skin.14 Lab mice, previously bred to be leptin-resistant, which predisposed them to diabetes, high blood pressure, insulin resistance and obesity, were treated with either the fermented juice or regular blueberry juice for three days.
"Consumption of fermented blueberry juice gradually and significantly reduced high blood glucose levels in diabetic mice," said lead study author Tri Vuong. "After three days, our mice subjects reduced their glycemia levels by 35 percent.”15 Among obesity-prone mice, meanwhile, those fed blueberry powder had reduced fat in their abdomen,16 and it’s possible that consuming this high-fiber berry as a snack may fulfill your appetite and cravings, helping people to lose weight too.
Consuming about 2 cups of these tasty fruits can even protect against DNA damage. Ten young volunteers were given that amount of blueberries (or a "placebo" of sorts). Blood tests done before and afterward were evaluated, and the blueberry group showed significantly reduced DNA damage within one hour.17
Along these lines, it’s possible that the benefits of blueberries extend to cancer protection. Blueberry extract has been shown to inhibit the growth and spread of breast cancer cells, for instance,18 as well as reduce tumor volume by 40 percent in rats.19 An anthocyanin extract from blueberries was used in other studies investigating breast cancer-fighting potential, resulting in significant reduction in cancer cell invasion ability and cell proliferation.20
Blueberry Superfood Smoothie Recipe
As a standard recommendation, I recommend keeping your total fructose consumption below 25 grams per day, and that includes fructose from fruit. If you have high blood pressure (or insulin resistance, diabetes, heart disease or other chronic diseases) you'd be wise to limit your fructose to 15 grams or less per day until your condition has normalized.
One cup of blueberries has 7.4 grams of fructose, so if you limit your intake from other sources, you can eat a cup of blueberries a day and still be well within the healthy limits.
You’ll want to choose organic blueberries whenever possible in order to minimize exposure to pesticide residues, and remember that fermented blueberries make an incredibly healthy addition to your diet.
For a quick smoothie recipe that’s high in antioxidants courtesy of one full cup of blueberries, try the Super Boost Power Smoothie recipe below. In addition to blueberries, you’ll gain added nutrition from whey protein, flax seeds and almond butter, making it a near-perfect choice when you need to fuel your body.
Super Boost Power Smoothie
- 4 cups rice milk or almond milk
- 1 large banana
- 2 tablespoons whey protein powder or 4 raw eggs
- 1 tablespoon bee pollen
- 1/4 cup almond butter
- 1 teaspoon spirulina or other green powder
- 2 tablespoons flax seeds
- 1 cup blueberries
- 1-inch piece fresh ginger
- 2 teaspoons lemon juice
- 2 ounces aloe vera juice
- 2 cups water
Place all ingredients into a blender. Mix until smooth. Makes four servings.
Source: mercola rss