Dr Dingle's Blog / prevention
Most people do not realise that the majority of the chronic illnesses we suffer from today are not only preventable but many are also reversible.So what better way to show you than individual case studies. But these are only a few of the hndreds and hundreds we have seen
Ann was diagnosed with systemic sclerosis at 24yrs and after 8 months she was totally able to reverse the condition. She is now 41yrs old.
Claire was diagnosed in 2009 as a type II diabetic suffering extreme cramps in my calves, feet, hands, abdominal muscles when bent over and in my neck muscles when yawning too hard. Night time was a nightmare – the worse one was when I had leg cramp ten times in one night, each episode taking up to 20 – 30 minutes to “walk off”. All her results are back within normal limits.
Robyn was suddenly taken ill in the in the early '90s and was diagnosed with everything from Multiple Chemical Sensitivity, Chronic Fatigue Syndrome to Fibromyalgia and became moderately depressed. She started changing her cleaning and personal care items and noticed small improvements. She eats no refined foods, avoids people and situations that don't have a positive input into our lives, including TV and newspapers. She meditates 20 minutes twice every day and goes to bed early and get up early ensuring a good 8-9hrs sleep every night. She now uses a treadmill each day, and can jog for 40 mins and hasn’t felt so good since that last day she played tennis 2 decades ago. She said she now feels about 40yrs old instead of 64yrs and is almost free from all the pain she endured for all that time. “Life is good (again)”.
At 61, Derek started to experience pain in my chest and was referred to a heart specialist and was told that my main artery was 75% to 80% blocked and another two were 30% blocked. He was told that although a good diet would help some, it was not possible to clear the blockages completely and he would require a stent. He made changes in his diet and lifestyle and a year later he went back for another stress test. His stamina and heart function were so greatly improved and his cardiologist could not believe it. The blockages were reduced to the point that they hardly registered at all. In fact, the cardiologist was so impressed he wanted Derek to talk to his team about what I did to get such amazing results. Derek is now 65 and says he feels great. “Peter’s book is filled with amazing information and is the first step to educating yourself”
At 65 Sam had shingles, sleep apnoea, 4 hours of ordinary sleep a night and acid reflux. After just one month of adopting an anti-inflammatory, antioxidant anti- acid producing diet and a few practices to help with his stress he felt like a new man. Still a long way to go he hasn’t felt this good in decades.
Rebecca was 16 and had almost every possible skin condition including eczema, psoriasis and acne. She was tired and because of her skin very antisocial. Applying some anti-inflammatory nutrients like aloe vera and green tea extract to her skin along with strong probiotics, prebiotics and foods to feed the gut microbiota Rebecca saw big changes in just 2 months. She also used low toxicity skin care products without parabens, phthalates and solvents and cut out sugar, sweets and processed food from her diet.
Belinda’s blood pressure was as high as 204/105. Yesterday it was 116/56. “Diet and drug companies are not overjoyed when I speak. I am 81 and the body is better now than 60 years ago”. The secret is she walks briskly 30 minutes a day and average 7,000 steps a day, eat five times a day (small nutritious portions) and avoid processed high salt and sugar, drink lots of water… lots of it. No sugar drinks. Belinda now talks to clubs, businesses and groups all over East Texas with a fun simple message of transforming to a healthy, happy life no matter how old or young you are.
Barry’s blood pressure recently shot up to over 220/110. He saw five different doctors. They all had the same answer: pharmaceuticals. Turns out the root cause was that I recently had an appendectomy, and during the surgery they had misaligned my C1 vertebra. Along with improved nutrition and a healthier lifestyle my chiropractor fixed me.
Amanda followed the program we teach and has one or two smoothies every day, supplements and off sugar and processed foods and within one month her blood pressure dropped more than 50 points, her psoriasis disappeared and she more energy than I had 20 years ago.
It is amazing what the body can do once it has the good nutrition and lifestyle factors to heal itself
Artificial sweeteners or Non-caloric artificial sweeteners (NAS) are commonly added to food with increasing controversy regarding their potential ability to promote metabolic imbalances and lead to weight gain instead of weight loss and diabetes type 2. Unfortunately, many people see these drinks and additives as being healthy. The research shows the opposite
The first report on NAS interactions with the microbiome dates back to the early 1980s. Since then, diets containing non-caloric artificial sweeteners (including saccharin, sucralose, and aspartame) have been linked to gut dysbiosis and glucose intolerance even at relatively low doses (5–7 mg/kg/d, equivalent to an adult consuming two to three cans of diet soda per day).
A study of Splenda, a nonnutritive sweetener containing 1% sucralose, found that the substance impaired the growth of gut bacteria in rats. Ace-K, like sodium saccharin and sodium cyclamate, belongs to sulfonamides, a chemical class associated with antimicrobial activity. In previous studies, saccharin was recognised to enrich the biosynthesis pathway of lipopolysaccharides (LPS) of the mouse gut microbiome, which is a common trigger of inflammation and leaky gut. Studies have also shown different and healthier bacterial diversity for nonconsumers compared to consumers of artificial sweeteners.
In another experiment where commercial formulations of saccharin, sucralose, or aspartame were added to the drinking water of lean mice for 11 weeks all three NAS-consuming groups developed glucose intolerance. NAS was also shown to induce changes in gut microbiota previously observed in T2DType 2 diabetes; notably, the over-representation of gram-negative Bacteroides and under-representation of gram-positive Clostridiales. Another study of 800 healthy and prediabetics showed variability in their after meal (postprandial) glucose responses to the same foods attributed to differences in gut microbiota. While a study of 345 Chinese volunteers revealed that diabetics have a decrease in butyrate-producing bacteria and an increase in opportunistic pathogens relative to healthy subjects.
On the positive side, the sugar alcohol xylitol inhibits the growth of some negative bacterial species including Streptococcus mutans. It is used as a food additive to prevent dental caries and in rats fed a high-fat diet, xylitol improved lipid/fat metabolism. Dietary supplementation with low- or medium-dose xylitol significantly positively altered the fecal microbiota composition in studied mice.
So what are you having in your next drink??
If you have been to one of my talks you would have heard me emphasize the importance of inflammation and the need to lower your body's chronic inflammation levels. Of course one of the major sources of ongoing chronic inflammation is the gut.
Inflammation is literally the body “on fire” and is a primary immune mechanism response of the body to a range of noxious stimuli. This can include infectious agents, such as bacteria or virus, oxidation or acidosis, damaged or diseased tissues.
The main function of inflammation is a short-term response to resolve infection and to repair damage in order to achieve homeostasis (balance) in the body. The ideal inflammatory response is therefore rapid and destructive, yet specific and very limited. This is the reddening and swelling you see around any infected or injured area. Most of us are familiar with redness, heat, swelling, and pain associated with inflammation. These symptoms are created by the activity of immune cells working to break down injured and dying tissues so that new, healthy ones can replace them.
Unfortunately, we have created a situation in which we now suffer from chronic low-level inflammation over decades of our lives as a result of our unhealthy and unbalanced lifestyles and diet. Chronic inflammation is being shown to be involved in the onset and the development of most, if not all, chronic illnesses that are currently at epidemic proportions in our society. These include atherosclerosis (damaged and blocked arteries), heart disease, stroke, obesity, neurodegenerative diseases, depression, Alzheimer’s, Parkinson’s disease, thyroid disorders, diabetes, asthma, autism, arthritis, celiac disease, eczema, psoriasis, multiple sclerosis, lupus, migraines, periodontal disease, sleep apnea, chronic kidney failure, cancer and ageing. This is a long list, yet these are only the most common conditions.
Even though chronic inflammation in the body is hard to detect, there are some common symptoms for which we should be on the lookout. These include the following:
Chronic pain in the joints and/or muscles
Allergies or asthma
Elevated blood pressure
Fluctuations in blood sugar levels
Gut issues (constipation or diarrhoea)
Aches, pain and sorenessThe inflammatory process is driven by the immune system. In order to reduce the incidence of disease, you must reduce inflammation, and to reduce inflammation you must identify and eliminate immune system trigger(s). The typical approach of allopathic medicine is to treat the symptoms of the disease itself, or the immune system (with immune-suppressive drugs) or inflammation (with anti-inflammatory drugs) directly without addressing the underlying cause of the disease. Sustainable health, on the other hand, looks at identifying and eliminating the sources of the inflammation to address the situation at its cause.
 Shelton and Miller 2010.
 Schwarzenberg and Sinaiko 2006.
 Taubes 2002; Ridker et al. 1997, 2000.
Many studies have been done on psychosocial factors and their impact on our health and even how long we live. More recently some of these have been able to show that having a sense of purpose can have many health benefits from lowering stress to reducing the risk of cardiovascular disease cancer and even living longer and it doesn’t matter how old you are. The benefits of perceiving and living a life directed toward a broader purpose are widespread and feeling that you have a sense of purpose in life may help you live longer, no matter what your age.
At a biological level having a sense of purpose has been shown to be associated with more positive body biochemistry and lower cortisol (stress) levels and lower levels of proinflammatory cytokines 1, the chemicals linked to cancer, heart attacks and chronic disease which represents one possible mechanism through which purpose in life influences mortality.
Having a purpose in life provides individuals with a sense of direction and goals for the future, as well as a marker of flourishing and a life well-lived. A strong sense of purpose buffers us from the storms of life. It like the roots of a tree, keeping us steady and grounded even in stormy weather. It provides us with a greater sense of controlling our direction in life, are more motivated and may even feel inspired. However, our sense of purpose is not to make money it has to be directed at something greater than yourself.
In research among teens and young adults having a sense of purpose enabled them to look beyond themselves to appreciate their role in the world and to build the psychological resilience necessary to overcome adversity. There is evidence that focusing on personally meaningful and valued goals can buffer the negative effects of stress by allowing individuals to reinforce a sense of who they are and that creating opportunities for individuals to cultivate a sense of purpose is important as we move forward as a society2.
Having a high sense of purpose in life has also been associated with lower risk of heart disease and stroke. In a review of 10 relevant studies with the data of more than 137,000 people they defined purpose in life as a sense of meaning and direction, and a feeling that life is worth living. Previous research has linked purpose to psychological health and well-being and this study found that a high sense of purpose is associated with a 23 percent reduction in death from all causes and a 19 percent reduced risk of heart attack, stroke, or the need for coronary artery bypass surgery or a cardiac stenting procedure. This is better than any drug and has multiple other benefits.
Previous studies have suggested that finding a purpose in life lowers risk of mortality above and beyond other factors that are known to predict longevity. Purposeful adults tend to outlive their peers and experience a diminished risk for both cognitive decline and disability in older adulthood. Moreover, having a purpose in life appears to lead to unique health benefits relative to other aspects of psychological well-being, such as having positive relations with others. In this study of 749 people with an average age of 60 found that the participants’ sense of purpose was positively associated with multiple positive health qualities including vigorous and moderate activity, vegetable intake, flossing, and sleep quality 3.
In another study of 6985 adults between the ages of 51 to 61 and a follow up for 14 years life purpose was significantly associated with all-cause mortality. Those with the strongest sense of purpose almost 2 and a half times more likely to be alive comparing those in the lowest life purpose category. Particularly compelling was the reduction in deaths from heart, circulatory, and blood conditions. Purpose had similar benefits for adults regardless of retirement status, a known mortality risk factor. And the longevity benefits of purpose in life held even after other indicators of psychological well-being, such as positive relations and positive emotions, were taken into account. These findings suggest that there's something unique about finding a purpose that seems to be leading to greater longevity 4.
These findings point to the fact that finding a direction for life, and setting overarching goals for what you want to achieve can help you actually live longer, regardless of when you find your purpose. So the earlier someone comes to a direction for life, the earlier these protective effects may be able to occur.
So what is your sense of purpose?
Write it down
1 Ryff CD, Singer BH, Dienberg Love G. Positive health: connecting well-being with biology. Philos Trans R Soc Lond B Biol Sci. 2004;359(1449):1383-1394.
2 A. L. Burrow, P. L. Hill. Derailed by Diversity? Purpose Buffers the Relationship Between Ethnic Composition on Trains and Passenger Negative Mood. Personality and Social Psychology Bulletin, 2013; DOI: 10.1177/0146167213499377
4 . P. L. Hill, N. A. Turiano. Purpose in Life as a Predictor of Mortality Across Adulthood. Psychological Science, 2014; DOI: 10.1177/0956797614531799
The intestinal microbiome is a plastic ecosystem that is shaped by environmental and genetic factors, interacting with virtually all of our organs, tissues and cells. One of the most important factors in regulating and controlling our microbiome is the pH or acid level.
While often mentioned in terms of the stomach the pH has a controlling role to play in the health of the whole GI tract from the mouth to the anus and changes in the “normal” pH anywhere in the gut can have large implications on the rest of the GI tract. The pH scale goes from 1 being very acidic to 14 being very alkaline. The level in our blood and tissues should be constantly around 7.36, neutral and the level in our GI trace varies from 1 to 8. We cover this a lot more in our book “Overcoming Illness” which focuses on the role of inflammation, oxidation and acidosis in illness.
After initial breakdown by chewing, food is churned by the smooth muscles of the stomach and is broken down by hydrochloric acid and stomach juices (enzymes). The pH of the stomach is highly acidic, around 1.5 (1.0-2.5) due to the hydrochloric acid which helps to kill harmful microorganisms, denature protein for digestion, and help create favorable conditions for the enzymes in the stomach juices such as pepsinogen. Not to mention sending messages along the GI tract that everything is working well in the stomach. If the pH is too high, say 3 or 4 (more alkaline) then the system does not work and you end up with digestive and health complications. For example, premature infants have less acidic stomachs (pH more than 4) and as a result are susceptible to increased gut infections. Similarly, the elderly show relatively low stomach acidity and a large number of people, more than 30%, over the age of 60 have very little or no Hydrochloric Acid in their stomachs.
Similarly, in gastric bypass weight loss surgery, roughly 60 percent of the stomach is removed. A consequence of this procedure is an increase in gastric pH levels that range from 5.7 to 6.8 (not 1.5) to making it more alkaline and as a result are more likely to experience microbial overgrowth. We see similar patterns in other clinical cases such as acid reflux in which treatment involves the use of proton-pump inhibitors and celiac disease where delayed gastric emptying is associated with reduced acidity and increased disease.
Unfortunately, acid reflux is often wrongly treated as a condition which involves the production of too much acid. It is in fact, the stomach finding it difficult to digest the foods, most commonly as a result not having enough acid to complete digestion and why medications (see later) which further reduce stomach acid have serious and deadly side effects on health, the digestive process and the gut microbiota. Acid reflux affects about 20% of the adult population and is much higher in older people which is consistent with the studies showing lower stomach acid as we age.
 Adbi. 1976; Martinsen et al., 2005.
 Carrion and Egan, 1990.
 Husebye et al., 1992.
 Machado et al., 2008.
 Amir et al., 2013.
 Usai et al., 1995.
Growing up as a child in the 60’s there was lots of space to play on the street, in the big back yards, nearby parks, creeks, the beach and lots of green spaces. While we we have lost a lot of these spaces research is showing that the more “green” we are surrounded with the the healthier it is for us. We exhibit more than just a preference for natural scenes and settings; we suffer health problems when we lose contact with our green surrounds. Increasing evidence indicates that nature provides restorative experiences that directly affect people's physical, social and mental well-being and health in a positive way including decreased mortality.
A recent study found that living in more densely vegetated areas was associated with fewer deaths from causes other than accidents. Using data from the Nurses’ Health Study researchers estimated a 12% lower rate of non-accidental death between women who lived in the most densely versus least densely vegetated areas. When looking at specific causes of death, the researchers estimated a 41% lower rate of kidney disease mortality, a 34% lower rate of respiratory disease mortality, and a 13% lower rate of cancer mortality in the women who lived in the greenest areas, compared with those in the least green areas. A study in the Netherlands found a lower prevalence of diseases in areas with more green space, including coronary heart disease and diabetes. In a cross-sectional study of 11,404 adults in Australia the odds of hospitalization for heart disease or stroke was 37% lower, and the odds of self-reported heart disease or stroke was 16% lower, among adults with highly variable greenness around their home, compared to those in neighborhoods with low variability in greenness. The odds of heart disease or stroke decreased by 7% per unit with every 25% increase in the level of greenness. In an interesting experiment where 14 children undertook two, 15 min bouts of cycling at a moderate exercise intensity while in one situation viewing a film of cycling in a forest setting and another with no visual stimulus. The systolic blood pressure (the top or higher number) 15 minutes after exercise was significantly lower following green exercise compared to the control condition. So if it works for kids it should also work for us we get older.
The rise in obesity is well documented and while there are many contributing factors a systematic review of green space research from sixty studies reported the majority (68%) of papers found a positive association between green spaces and obesity-related health indicators. One study found that increased vegetation was associated with reduced weight among young people living in high population densities and across eight European cities, people were 40% less likely to be obese in the greenest areas. Overall, the majority of studies found some evidence of a relationship with weight and green space. The lower rates of obesity, adverse health and improved health outcomes may be attributable to higher levels of physical activity, such as neighborhood walking which is positively influenced by the natural environment. Walking is the most popular physical activity particularly as we age, and levels of recreational walking have been linked the distance to and attractiveness of local parks and ovals. Many studies have reported that adults with access to a large high-quality park within walking distance (within 1600 m) from home have elevated levels of walking and and in general live longer. In a review of 50 studies twenty studies (40%) reported a positive association between green space and physical activity, including older adults.
Being around vegetation can lead to better mental health and less stress, positive emotions, focus and attention, as well as reduced stress. While walking itself can reduce stress, walking in a natural setting provides greater stress-relieving benefits. Accessible green spaces are ‘escape facilities’, and lack of access to green space contributes to poor mental health. Some of the more potent restorative effects of nature relate to being able to ‘get away’ from everyday settings and immerse oneself in an extensive natural setting that creates a sense of being in a ‘whole other world’.
Perhaps as we decide to age healthier we need to spend more time near green spaces.
Another reason to add some of the cabbage family to your daily diet, preferably raw is because of their gut healing properties and how they promote gut health through the gut microbiome. The Brassica family including cabbage, broccoli, brussel sprouts, kale, arugula (rocket), bok choy, cauliflower, collard greens, radish, turnip and others have been recognized for their gut healing and gut health properties for hundreds of years and modern epidemiologic studies have shown a frequent consumption of cruciferous vegetables is associated with lower risk of cancer, especially cancers of the digestive tract, bladder, breast, prostate, and lung. However, only now are we recognizing that many of these benefits are mediated through the microbiome and that their frequent consumption alters the composition of the microbiome.
Cruciferous vegetables are a rich source of glucosinolates a precursor to the Isothiocyanates (ITC), which exhibit powerful biological functions in fighting cancers, cardiovascular, neurodegenerative diseases and gut healing. The Isothiocyanates are a by product of specific plant enzymes (myrosinase) active during chewing or crushing when broccoli is consumed raw or lightly steamed, however, like all enzymes myrosinase is deactivated by cooking and ingestion of cooked broccoli typically provides only about one tenth the amount of isothiocyanates as that from raw broccoli. So to maximize the gut healing, gut health and overall benefits of these foods they are best eaten raw or just lightly steamed.
Instead when cooked cruciferous vegetables are consumed, gut bacteria are mainly responsible for ITC production in the gut. This is highlighted after taking oral antibiotics, the ITC’s availability and uptake decreases after eating cooked cruciferous vegetable. It also appears that there is considerable difference in the ability of individuals, due to individual differences in gut microbial community, to produce the isothiocyanates. Although, the gut community’s ability is altered over just 4 days. In one study feeding raw or cooked broccoli for four days or longer both changed the microbiota composition and caused a greater production of isothiocyanates. Interestingly, a three-day withdrawal from broccoli reversed the increased microbial metabolites suggesting that the microbiota requires four or more days of broccoli consumption and is reversible.
The lactic acid bacteria appear to have myrosinase-like activity and the fermented Brassica food products, such as sauerkraut and kimchi, are particularly rich in Lactobacillus, and a diet rich in Brassica may promote Lactobacillus growth in the colon.
Despite what we are often told the overwhelming evidence shows that Type 2 diabetes is a diet and lifestyle illness. It also shows that when you reverse the conditions that caused it the disease is also reversible.
Type 2 diabetes (T2D) is a chronic disease closely linked to the epidemic of obesity that requires long-term medical attention to limit the development of its wide range of complications. Many of these complications arise from the combination of resistance to insulin action, inadequate insulin secretion, and excessive or inappropriate glucagon secretion. Approximately 10% of the population of the USA and Canada have a diagnosis of T2D, and the morbidity and mortality rates associated with it are fairly high. The economic burden of T2D in the USA is $245 billion and around $20 billion in Australia.
This case documents three patients referred to the Intensive Dietary Management clinic in Toronto, Canada, for insulin-dependent type 2 diabetes. It demonstrates the effectiveness of therapeutic fasting to reverse their insulin resistance, resulting in cessation of insulin therapy while maintaining control of their blood sugars. In addition, these patients were also able to lose significant amounts of body weight, reduce their waist circumference and also reduce their glycated haemoglobin level.
These three cases exemplify that therapeutic fasting may reduce insulin requirements in T2D. Given the rising cost of insulin, patients may potentially save significant money. Further, the reduced need for syringes and blood glucose monitoring may reduce patient discomfort.
Therapeutic fasting has the potential to fill this gap in diabetes care by providing similar intensive caloric restriction and hormonal benefits as bariatric surgery without the invasive and dangerous surgery. During fasting periods, patients are allowed to drink unlimited amounts of very low-calorie fluids such as water, coffee, tea and bone broth. A general multivitamin supplement is encouraged to provide adequate micronutrients. Precise fasting schedules vary depending primarily on the patient’s preference, ranging from 16 hours to several days. On eating days, patients are encouraged to eat a diet low in sugar and refined carbohydrates, which decreases blood glucose and insulin secretion.
This means that patients with T2D can reverse their diseases without the worry of side effects and financial burden of many pharmaceuticals, as well as the unknown long-term risks and uncertainty of surgery, all by means of therapeutic fasting.
Depression itself is not a disease, but a symptom of an underlying problem. A new theory called the “Immune Cytokine Model of Depression” holds that depression is a “multifaceted sign of chronic immune system activation,” inflammation. Depression may be a symptom of chronic inflammation. And a large body of research now suggests that depression is associated with a low-grade, chronic inflammatory response and is accompanied by increased oxidative stress—not a serotonin imbalance.
Researchers discovered in the early 1980s that inflammatory cytokines produce a wide variety of psychiatric and neurological symptoms that perfectly mirror the defining characteristics of depression. Cytokines have been shown to access the brain and interact with virtually every mechanism known to be involved in depression including neurotransmitter metabolism, neuroendocrine function, and neural plasticity.
This is now supported by increasing lines of scientific evidence including:
- Depression is often present in acute, inflammatory illnesses.
- Higher levels of inflammation increase the risk of developing depression.
- Administering endotoxins that provoke inflammation in healthy people triggers classic depressive symptoms.
- One-quarter of patients who take interferon, a medication used to treat hepatitis C that causes significant inflammation, develop major depression.
- Up to 50% of patients who received the cytokine IFN-alpha therapy to help treat cancer or infectious diseases developed “clinically significant depression.”
- An experiment involving the administration of a Salmonella typhi vaccine to healthy individuals produced symptoms of fatigue, mental confusion, psychomotor slowing and a depressed mood. These symptoms correlated with the increase in cytokine concentrations.
- Remission of clinical depression is often associated with a normalization of inflammatory markers.
- There is now a large body of literature regarding laboratory animals demonstrating that cytokines … can lead to a host of behavioural changes overlapping with those found in depression. These behavioral changes include decreased activity, cognitive dysfunction and altered sleep.
- All the activities associated with reducing the prevalence of depression and depression symptoms are anti-inflammatory. These include increased sunlight and time spent outside, exercise and physical activity, relaxation and meditation techniques, healthy eating as well as administering anti-inflammatory nutritionals.
There is further support from large epidemiological studies. A number of longitudinal studies have now shown that inflammation in early adulthood predicts depression at a later stage in life. In a large longitudinal study, the risk for depression and psychotic experiences in adolescence was almost two-fold higher in individuals with the highest compared to the lowest levels of inflammation as indicated by interleukin-6 (IL-6) levels in childhood. Children who were in the top third of IL-6 levels at the age of 9 years were 55% more likely to be diagnosed with depression at the age of 18 than those with the lowest childhood levels of IL-6. Children in the highest level of IL-6 levels at the age of 9 were also 81% more likely to report psychotic experiences at the age of 18. A study of more than 73,000 men and women showed increasing inflammation levels were associated with increasing risk for psychological distress and depression. Increasing inflammation (CRP) levels were also associated with increasing risk for hospitalization with depression.
In support of the inflammation depression link, recent studies have found a significant link between the dietary inflammatory index (DII) and risk of depression. In an Australian study of 6,438 middle-aged women, those with the most anti-inflammatory diet had an approximately 26% lower risk of developing depression compared with women with the most pro-inflammatory diet. Similarly, a study in the UK examined the DII and recurrent depressive symptoms over five years in 3,178 middle-aged men and 1,068 women. Researchers found that for each increment of 1 level of DII score (increased inflammation), odds of depression increased by 66% in women, whereas in men the risk increased by only 12%. In a study of 15,093 university graduates in Spain, those on the highest DII (strongly pro-inflammatory diet) had a 47% risk of depression compared with those in the bottom, with a significant dose-response relationship, which means as the diet became more inflammatory it increased the risk of depression. Further analysis also showed the association between DII (the inflammatory diet) and depression was stronger among participants older than 55 years, with an increased risk of 270% and those with cardiometabolic comorbidities (high blood pressure, diabetes, etc.) had an 80% increased risk of depression. In a study of 43,685 women (aged 50–77) without depression at baseline, the risk of developing depression was 41% higher if they were on the highest compared to the lowest Dietary Inflammatory Index diet.
Oxidative stress is closely related to the inflammatory pathway in particular. Pro-inflammatory cytokines are produced in reaction to oxidative stress and oxidative stress in turn amplifies the inflammatory response. High cortisol levels have been associated with increased levels of oxidative damage. Depression has been associated with increased oxidative stress and increased severity of depression is associated with increased systemic oxidatively generated DNA and RNA damage. Severe depression is associated with increased systemic oxidatively generated RNA damage, which may be an additional factor underlying the somatic morbidity and neurodegenerative features associated with depression. In a meta-analysis, 1,308 subjects depressed persons had increased oxidative stress and decreased anti-oxidant defences (as measured by 8-OHdG and F2-isoprostanes). The results indicate that depression is associated with increased oxidative damage to DNA and lipids. The brain is particularly vulnerable to oxidative damage due to its high oxygen consumption and low antioxidant defences. Sustained oxidative brain damage during a depressive episode may make a sufferer prone to developing another depressive episode. Therefore, it has been hypothesized that exposure to oxidative stress could be an explanatory mechanism in the remitting and chronic course of depressive disorders. There is also evidence from post-mortem studies suggesting that in depression oxidative stress is increased and antioxidants are decreased in the brain.
A study of 37 patients with bipolar disorder showed that bipolar disorder is associated with increased oxidatively generated damage to nucleosides, which could be contributing to the increased risk of medical disorders, shortened life expectancy, and the progressive course of illness observed in bipolar disorder. Another study showed increased oxidative stress as indicated by increased nitric oxide (NO) and lipid peroxidation, measured by thiobarbituric acidic reactive substance (TBARS) assay in patients with bipolar disorder.
There is evidence suggesting that antioxidants are decreased in depression, illustrated by lower antioxidant levels, including carotenoids, and antioxidant enzymes. There is some evidence to suggest that antidepressants have antioxidant properties and may act through reducing pro-inflammatory cytokines and ROS production and improving levels of antioxidants such as superoxide dismutase.
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