Most of us know that blueberries are healthy – but what do we know to back up this claim? Blueberries were an important food source for Native American tribes in the east; berries, leaves and roots were also considered medicinal. In the last 10 years there has been an increasing research in compounds in blueberries that may prevent disease. Wild blueberries have been found to have a higher antioxidant capacity than cranberries, strawberries, plums, and raspberries. Here is some of the data.
The Brain: blueberries contain ‘anthocyanins’ - pigments found in red/purplish fruits and vegetables – such as purple cabbage, beets, blueberries, cocoa, cherries, raspberries and purple grapes. These pigments are antioxidant and anti-inflammatory, helping to protect brain cells and enhance their ability to signal one another. Researchers at the University of Cincinnati worked with a small group of older adults with early memory changes. Those who drank 2 cups of blueberry juice per day showed improved memory and learning, reduced depression and improved glucose levels after 3 months. Similar results have been found in experimental animals. A study from Reading University in England on people of all ages showed that people taking 200 gm (2 cups) of blueberries in a morning smoothie did better on mental tasks 5 hours later compared to people having a smoothie without blueberries. Two cups is a large (and expensive) amount of blueberries. Strawberries, cocoa and raspberries were said to have similar effects on the brain. A study at Tufts University in Boston on experimental animals showed that blueberries improved motor and navigational skills.
Cancer prevention: Studies at the University of Illinois have looked at 3 phases of cancer development – initiation, promotion and proliferation (metastasis). Various compounds in wild blueberries are helpful in prevention all 3 phases, Researchers at several universities have looked at the ability of blueberry extracts to inhibit the growth of prostate, colon, breast and cervical cancer cells. The work looks promising, but is still laboratory-based and preliminary.
Urinary Tract infections: Rutgers University has a Blueberry-Cranberry Research Center; they have found that both fruits prevent bacteria from adhering to urinary tract tissues, and this help prevent urinary tract infections. A half-cup of blueberries a day may be sufficient for this benefit.
Heart Health: A study on rats at Tufts University and the National Institute on Aging showed that when the animals had a major artery to their hearts tied off, those on a blueberry enriched diet had less damage to their hearts than those on a control diet, and were less likely to develop heart failure. Several studies in Canada and at UC Davis have shown that blueberries can reduce LDL Cholesterol (the kind that can lead to heart attack and stroke).
Diabetes: The anthocyanins in blueberries have been found to reduce blood sugar levels in rodents bred to develop diabetes, according to studies at North Carolina State University. This may mean that blueberries and their juice are safe for people with diabetes. People with high blood sugar should proceed with caution and check their levels. This may be a helpful fruit.
Blueberries and their European cousin, bilberries, are now being grown all over the world. There is said to be a blueberry juice craze in Japan, with the idea that blueberries reduce eyestrain. This has also been studied with bilberries in Europe. Most markets carry frozen blueberries all year, and fresh ones in the summer. They are a good investment.
Sadja Greenwood, MD, MPH Back issues here. Leave me a message!
Monday, May 31, 2010
Monday, May 10, 2010
Go to Health: The Second Brain in Your Gut!
We have an extensive network of nerve cells (neurons) lining our guts – some call it ‘the second brain’. This nervous system contains about 100 million neurons, more neurons than the spinal cord or the peripheral nervous system (sensory and motor nerves relaying impulses all over the body). The second brain consists of sheaths of neurons embedded in the long tube of our gut, from the esophagus to the anus, It gives the necessary stimuli for mechanical mixing of food in the stomach, breaking down particles, chemical processing, and rhythmical muscle contractions that move food down the intestinal tract. We can feel the inner world of our gut when we pay attention, especially if it gives us pain from malfunction (think of the cramps of dysentery, the discomfort of gas or the pain of appendicitis). Think of ‘butterflies in the stomach’ when you are anxious, or in love, or a ‘knot’ in your midsection when you are asked to do something you don’t want to do! Sudden fear, often felt in the belly, will stop digestion to route blood to your muscles for flight or fight. These feelings can come on before the brain in your head has understood the situation. The second brain works fast!
The second brain makes many neurotransmitters, just like the brain in our heads. Over 80% percent of the body’s serotonin is located in the gut, where it is made from tryptophan (an amino acid found in the proteins we eat). Serotonin regulates intestinal movements. If irritants are present in our food, gut nerve cells release more serotonin, making the gut move faster to get rid of the noxious substance. It can also induce vomiting. Gut serotonin is regularly released into the blood stream, where it is taken up and stored by blood platelets, and used to help in the clotting process when a cut or wound occurs. Serotonin is also important in the regulation of mood, appetite, sleep, muscle contraction and some cognitive processes.
The SSRI antidepressants (Prozac, Paxil, Zoloft, Celexa, Lexapro and others) increase serotonin levels and are highly effective for some people to alleviate depression and anxiety. However they can also can affect the gut and bone strength. Some, but not all, users have abdominal symptoms with these drugs. Serotonin’s role in bone strength is under study - bones get weaker in the presence of more serotonin. Users of SSRIs have been shown to have greater rates of bone loss than average, and should be extra careful to protect their bones with exercise, vitamin D and special medications if needed.
In addition to serotonin, the brain in the gut also makes the neurotransmitters dopamine, glutamate, norephinephrine and nitric oxide, and two dozen small brain proteins, called neuropeptides. Endorphins, that relieve pain, are also made in the gut, as well as tranquilizing substances. The food-mood connection is real.
You can keep your gut happy and healthy by some simple daily habits. Take a probiotic every morning (keep it refrigerated) to ensure a predominance of healthy bacteria in your colon. Eat plenty of simple plant food to ensure good levels of fiber, vitamins, minerals and other plant nutrients. Go for dried figs, dates or bananas instead of cake and candy. You know the rap! Have you tried dried bananas? Wow!
Sadja Greenwood, MD, MPH back columns on this blog. Leave me your thoughts.
The second brain makes many neurotransmitters, just like the brain in our heads. Over 80% percent of the body’s serotonin is located in the gut, where it is made from tryptophan (an amino acid found in the proteins we eat). Serotonin regulates intestinal movements. If irritants are present in our food, gut nerve cells release more serotonin, making the gut move faster to get rid of the noxious substance. It can also induce vomiting. Gut serotonin is regularly released into the blood stream, where it is taken up and stored by blood platelets, and used to help in the clotting process when a cut or wound occurs. Serotonin is also important in the regulation of mood, appetite, sleep, muscle contraction and some cognitive processes.
The SSRI antidepressants (Prozac, Paxil, Zoloft, Celexa, Lexapro and others) increase serotonin levels and are highly effective for some people to alleviate depression and anxiety. However they can also can affect the gut and bone strength. Some, but not all, users have abdominal symptoms with these drugs. Serotonin’s role in bone strength is under study - bones get weaker in the presence of more serotonin. Users of SSRIs have been shown to have greater rates of bone loss than average, and should be extra careful to protect their bones with exercise, vitamin D and special medications if needed.
In addition to serotonin, the brain in the gut also makes the neurotransmitters dopamine, glutamate, norephinephrine and nitric oxide, and two dozen small brain proteins, called neuropeptides. Endorphins, that relieve pain, are also made in the gut, as well as tranquilizing substances. The food-mood connection is real.
You can keep your gut happy and healthy by some simple daily habits. Take a probiotic every morning (keep it refrigerated) to ensure a predominance of healthy bacteria in your colon. Eat plenty of simple plant food to ensure good levels of fiber, vitamins, minerals and other plant nutrients. Go for dried figs, dates or bananas instead of cake and candy. You know the rap! Have you tried dried bananas? Wow!
Sadja Greenwood, MD, MPH back columns on this blog. Leave me your thoughts.
Wednesday, May 5, 2010
Go to Health: Important Updates on Vitamin D and Chocolate
Vitamin D
Researchers at the University of Copenhagen have just published an important paper - explaining the mechanisms by which vitamin D helps our immune systems fight off viral and bacterial infections. T cells, the cells that detect and kill foreign pathogens must be triggered into action by vitamin D. When the T cell meets a clump of bacteria or viruses, it extends a signaling device - an antenna - known as a vitamin D receptor. If it finds enough vitamin D in the blood, it is transformed into a ‘killer’ cell that will attack and destroy all cells carrying traces of a foreign pathogen, or into a ‘helper’ call that assist the immune system in acquiring ‘memory’. This memory enables the immune system to recognize the pathogen at the next encounter and launch an enhanced response. If vitamin D blood levels are low, T cells are less likely to be transformed into killer or helper cells.
Prior studies have shown that people with higher blood levels of vitamin D are less likely to get respiratory infections. The Copenhagen group has found a mechanism that may explain this. Many local residents suffered from prolonged colds and coughs this winter – getting adequate D is good preventive medicine and may help from now on..
We are heading into summer and the sun is back – so you can get D from safe sun exposure as well as from pills. While the majority of dermatologists discourage exposing skin to sunlight without sunscreen of 15 spf or higher, a few say that 10 minutes a day of exposure of the arms, legs and back is safe and can result in good levels of vitamin D being formed. Avoid sun exposure on your face by wearing sunscreen and a hat, because of skin damage and wrinkles. Get a blood level of 25 hydroxy vitamin D at the clinic, and aim for 35-40 ng/ml by taking vitamin D3 pills as well as safe sun exposure. Most doctors are now suggesting 1000-2000 IU of D daily in pill form.
A recent study from the University of South Carolina, funded by the National Institutes of Health, showed that pregnant women who took 4000 IU of vitamin D daily, starting at three months of pregnancy, had half the usual risk of premature delivery and ‘small for dates’ babies, and a 25% lower risk of respiratory infections, vaginal infections and gum problems. The pregnant women also had less diabetes, high blood pressure and ‘eclampsia’ - a dangerous complication. The university is now studying extra vitamin D for nursing mothers. (If you are pregnant or nursing, check with your doctor!)
Chocolate
In a previous column on chocolate, I wrote that chocolate increases the amount of nitric oxide (NO) in the body. . NO is a gaseous ‘signaling molecule’ that crosses membranes and freely diffuses between cells. It signals the muscular coating around arteries to relax, thus improving blood flow and lowering blood pressure. Another protective effect of NO is its inhibition of blood clotting and the adhesion of white blood cells to the lining of blood vessels. These findings tie in with a joint Swedish-US study that showed that heart attack patients who had eaten chocolate at least twice a week during the year before their attack were 66% less likely to die at that time from cardiac causes. Over the following 8 years, the risk of cardiac mortality went down as chocolate consumption went up – there was a 44% reduction of risk associated with eating chocolate up to once a week. The authors of this study cautioned that chocolate is not a health food, being high in sugars and fats. However, there are healthy ways to eat it. Buy unsweetened cocoa powder (Green and Black is organic and fair trade) and put it in a shake, sweetened with a date or two, pomegranate concentrate, banana, xylitol or stevia. Mash a banana and some peanut butter, add unsweetened cocoa powder, and eat it right away, or put it on toast.
Here’s another benefit – researchers at the University of Barcelona put 47 men and women (age 55 and older) on diets including 1/4th cup unsweetened cocoa powder and skim milk , to be taken twice a day, and found, after a month, that those who drank cocoa had lower levels of inflammatory markers associated with heart disease, and significantly higher HDL cholesterol (the good kind). People sensitive to caffeine should be careful with these amounts of cocoa, as they give a stimulant effect.
Dear readers – I hope your spirits are rising with the sun and the wonderful green plants in your gardens and all around you.
Sadja Greenwood, MD,MPH - back issues at on this blog. Leave me a message!
Researchers at the University of Copenhagen have just published an important paper - explaining the mechanisms by which vitamin D helps our immune systems fight off viral and bacterial infections. T cells, the cells that detect and kill foreign pathogens must be triggered into action by vitamin D. When the T cell meets a clump of bacteria or viruses, it extends a signaling device - an antenna - known as a vitamin D receptor. If it finds enough vitamin D in the blood, it is transformed into a ‘killer’ cell that will attack and destroy all cells carrying traces of a foreign pathogen, or into a ‘helper’ call that assist the immune system in acquiring ‘memory’. This memory enables the immune system to recognize the pathogen at the next encounter and launch an enhanced response. If vitamin D blood levels are low, T cells are less likely to be transformed into killer or helper cells.
Prior studies have shown that people with higher blood levels of vitamin D are less likely to get respiratory infections. The Copenhagen group has found a mechanism that may explain this. Many local residents suffered from prolonged colds and coughs this winter – getting adequate D is good preventive medicine and may help from now on..
We are heading into summer and the sun is back – so you can get D from safe sun exposure as well as from pills. While the majority of dermatologists discourage exposing skin to sunlight without sunscreen of 15 spf or higher, a few say that 10 minutes a day of exposure of the arms, legs and back is safe and can result in good levels of vitamin D being formed. Avoid sun exposure on your face by wearing sunscreen and a hat, because of skin damage and wrinkles. Get a blood level of 25 hydroxy vitamin D at the clinic, and aim for 35-40 ng/ml by taking vitamin D3 pills as well as safe sun exposure. Most doctors are now suggesting 1000-2000 IU of D daily in pill form.
A recent study from the University of South Carolina, funded by the National Institutes of Health, showed that pregnant women who took 4000 IU of vitamin D daily, starting at three months of pregnancy, had half the usual risk of premature delivery and ‘small for dates’ babies, and a 25% lower risk of respiratory infections, vaginal infections and gum problems. The pregnant women also had less diabetes, high blood pressure and ‘eclampsia’ - a dangerous complication. The university is now studying extra vitamin D for nursing mothers. (If you are pregnant or nursing, check with your doctor!)
Chocolate
In a previous column on chocolate, I wrote that chocolate increases the amount of nitric oxide (NO) in the body. . NO is a gaseous ‘signaling molecule’ that crosses membranes and freely diffuses between cells. It signals the muscular coating around arteries to relax, thus improving blood flow and lowering blood pressure. Another protective effect of NO is its inhibition of blood clotting and the adhesion of white blood cells to the lining of blood vessels. These findings tie in with a joint Swedish-US study that showed that heart attack patients who had eaten chocolate at least twice a week during the year before their attack were 66% less likely to die at that time from cardiac causes. Over the following 8 years, the risk of cardiac mortality went down as chocolate consumption went up – there was a 44% reduction of risk associated with eating chocolate up to once a week. The authors of this study cautioned that chocolate is not a health food, being high in sugars and fats. However, there are healthy ways to eat it. Buy unsweetened cocoa powder (Green and Black is organic and fair trade) and put it in a shake, sweetened with a date or two, pomegranate concentrate, banana, xylitol or stevia. Mash a banana and some peanut butter, add unsweetened cocoa powder, and eat it right away, or put it on toast.
Here’s another benefit – researchers at the University of Barcelona put 47 men and women (age 55 and older) on diets including 1/4th cup unsweetened cocoa powder and skim milk , to be taken twice a day, and found, after a month, that those who drank cocoa had lower levels of inflammatory markers associated with heart disease, and significantly higher HDL cholesterol (the good kind). People sensitive to caffeine should be careful with these amounts of cocoa, as they give a stimulant effect.
Dear readers – I hope your spirits are rising with the sun and the wonderful green plants in your gardens and all around you.
Sadja Greenwood, MD,MPH - back issues at on this blog. Leave me a message!
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