Depression and Diet
I have been able to find only one small study on the frequency of depression by type of diet, outside of the omega-3 research. That study of 80 people found that vegan vegetarians did have less depression. However, that is an extremely small study and not at all a controlled study. There is a huge amount of evidence that diet has a dramatic impact on human health. Some of this research shows that diet has a major impact on the development of Alzheimer's dementia, Parkinson's Disease, and multiple sclerosis, all nervous system diseases. Also, a fair number of studies have found that depressed patients are low in a variety of vitamins, which suggests that their diets might be less than ideal.
My review of the studies establishing what is the most healthy diet would take too much room for a booklet on depression. However, I agree strongly with Dr. Walter Willett of Harvardís School of Public Health (Newsweek 1/20/03, pg 47-54). Dr. Willett has dramatically revised the USDA Food Pymamid so that it reflects the findings of large-scale prospective dietary research that have been published over the last 10 years. Dr. Willettís pyramid recommends that butter, red meats (mammal meats, i.e., beef, pork, mutton) and refined starches (sugar, white rice, white bread, regular pasta, and potatoes) be used sparingly, if at all.
Dr. Willett recommends 1-2 servings per day of dairy or a calcium supplement. This is acceptable advice for women, who are at higher risk than men for osteoporosis, but will actually kill a significant number of men over the age of 45 since dairy and calcium supplements more than triple the rate of prostate cancer. I encourage all men, especially those over 45, to abstain from dairy products. For women, the dairy should be in the form of skim or 1% milk, not cheese, or, better yet, use calcium supplements. In fact, avoiding salt is a much better way to avoid osteoporosis and high blood pressure than increasing calcium. Calcium is present in adequate amounts for the non-salt user in numerous non-meat foods. Salt actually causes the kidneys to excrete more calcium, which results in calcium being taken out of the bones to replace this loss.
Fish, poultry, and eggs are permitted up to twice a day by Dr. Willett. I would modify this to encourage seafood several times a week or fish oil or flax daily. Nuts and legumes (beans, soybeans, peas, and lentils) are recommended 1 to 3 times a day. I would modify this to nuts at least once a day and legumes 1 to 2 times a day. Vegetables are recommended " in abundance" and fruits 2 to 3 times a day. Whole-grain foods are recommended "at most meals" and plant oils "at most meals." I would modify the latter to olive, or canola oil daily with Smart Balance as a margarine if margarine is needed. Willett recommended daily multivitamins and alcohol in moderation unless contraindicated. Salt should also be strictly prohibited. Potassium chloride salt substitute is actually quite healthy, but the flavor wouldnít please many salt addicts. Lite salt is half salt and half potassium chloride and is an acceptable compromise for the salt addict. It often takes a year or more to fully eliminate salt from oneís diet.
Whether such a diet would help depression, no one knows. There are no studies of the depression rates of vegan vegetarians who most resemble the Willett diet. Also, while many vegans eat a very healthy diet, large numbers of other vegans get too little protein, vitamin B-12, selenium, and omega-3 fatty acids. Actually, the average vegetarian is lower in all of these than the average omnivore. While it is easy to eliminate these deficiencies by eating enough beans, nuts, and flax seeds or oil and taking a couple vitamin pills daily, many vegans are not doing this. There is also absolutely no research on whether organic foods helps health in any way, except for one study showing an organic food diet no benefit in improving with sperm quality of organic farmers vs. traditional farmers. I personally think that organic foods are not worth the added cost.
While there is little depression research outside of the omega-3 and vitamin studies, an increasingly large number of studies show that diet helps prevent a number of other diseases of the brain. There are many studies showing that following the advice in Dr. Willettís pyramid will lower the risk of Alzheimerís Disease. Spinach, blueberries, fish oil, vegan diets, low salt, and low animal fat diets have all been found associated with lower rates of dementia. One study with schizophrenia finds faster recovery in countries with very low levels of meat intake. Several studies show that butter, cheese, and meats, primarily mammal or red meats, increase the rate of multiple sclerosis considerably. Dairy products almost triple the rate of Parkinsonís Disease in American men. Since these studies show that mammal products damage the nervous system in several different ways, it seems reasonable to conclude that they very likely increase depression as well.
I recommend totally eliminating beef, pork, mutton, butter, and cheese from the diet and following the modified Willett diet. Even if it doesnít help depression, and I am confident it will, it is sure to make you a more healthy person. Having said this, although I try to follow a vegan diet with the exception of daily fish oil capsules, I do cheat and eat mammal products maybe twice a year, and eggs and fowl still more often. Thus, I could hardly expect patients to do better than I do, although if they did, it would likely be to their benefit.
Meat, Mammal Meat Bad, Fruits & Veggies Prevent Alzheimerís: Case Western University School of Medicine and University Hospitals of Cleveland, Ohio are now saying that a diet rich in fruits and veggies and low in red meat may actually prevent Alzheimer's. Compuserve 7/18/02
Meat May Increase Dementia in US: A small 7th Day Adventist study of 272 patients with dementia found that vegans and vegetarians were less likely than "heavy" meat eaters to develop dementia. The risk factor rates were RR 2.18 and 2.99 when past meat consumption was taken into consideration. Giem, Neuroepidemiology Ď93;12:28
Diet in 8 Countries: Animal Fat Bad, Fish OK for Schizophrenia: Study found that 97% of the variance in patient recovery between countries could be attributed to dietary variations with high total fat intake and high intake of land animal and bird fat especially (p=.0002). There is a favorable recovery linkage, tho not as strong, linked to a higher intake of fats from fish, seafood, and vegetables (p>.10). Used data from 8 national centers participating in WHO international 2-year f/u study. Incidence of schiz similar in all countries. Christiansen, Denmark, Acta Psychia Scand 88;78:587
Childhood Meat Intake Major Factor in Multiple Sclerosis in Russia: MS patients reported a higher frequency of: 1) tonsillitis; 2) allergic reactions age 15; 3) head trauma below age 16; 4) a predominant meat vs. vegetable diet during childhood. Stratified analysis and logistic regression pointed to "meat predominance" as the most significant risk factor. Study of 177 Moscow patients. Acta Neurol Scand 1996 Dec;94(6):386-94
Meat and Dairy Associated with Multiple Sclerosis in Germany: J Clin Epidemiol 1994 Jan;47(1):43-8. German study found diet and latitude factors in MS. Higher latitudes have more MS, possibly due to lower levels of Vitamin D.
Meat, Whole Milk, and possibly Potatoes Associated with Multiple Sclerosis in Croatia: daily consumption of different quantities of full fat unskimmed milk (OR 21.7; chi 2 42.34; LL 7.12), potatoes with lard and fresh or smoked meat (OR 20.7; chi 2 15.52; LL 2.72), and new potatoes (OR 20.7; chi 2 15.52; LL 2.72). 46 pt and 92 controls. Neuroepidemiology 1993;12(4):234-40
Pork, Fats Implicated in Multiple Sclerosis in Several Countries: prevalence rates of multiple sclerosis (MS) in several countries and the corresponding per capita consumption of fat, beef and pork was investigated. A significant correlation was obtained between prevalence of multiple sclerosis and fat intake (r = 0.63, p less than 0.01), total meat intake (r = 0.61, p less than 0.01) and pork consumption (r = 0.87, p less than 0.001). There was no significant correlation with beef consumption. Med Hypotheses 1986 Jul;20(3):279-82
Milk Increases Parkinsonís Disease in U.S. Men: Honglei Chen of the Department of Nutrition at the Harvard School of Public Health in Massachusetts, found that dietary intake of dairy products is associated with an increased risk of developing Parkinsonís in men, but not in women (Annals of Neurology 2002;52:793-801). Prospective health profressionals and nurses studies found 2.9 servings vs. under 1 serving per day associated with 80% increase and this level over 6 years associated with 170% increase (2.7 relative risk). Some cases been linked to viruses, toxins, and drugs. Oxidative damage has also been thought to contribute, and some studies have found that antioxidants can protect against the progression of the disease.
Blueberries Prevent Mouse Dementia: Blueberries high in flavonoid pigments which are strong antioxidants. Mouse study found spinach, strawberries, and blueberries all helped reduce loss of test performance, e.g. mazes, balancing, but that only blueberries showed improvements in every test of motor coordination. James Joseph, Human Nutrition Research Center on Aging, Tufts, J Neuroscience 9/15/99. Amount equal to 1 cup blueberries per day. Recommends variety of pigmented fruits and vegetables as best since different anti-oxidants work in different ways.
Blueberries, Spinach Prevent Rat Dementia: Rats fed a diet rich in spinach reversed a normal loss of learning that occurs with age, according to a study by researchers at the University of South Florida. The study was presented at the Society for Neuroscience's annual meeting in San Diego. Rats fed a normal diet that contained 2 percent freeze-dried spinach. Blueberries are also rich in antioxidants. A study by researchers at the University of Houston at Clear Lake and the Universidad Nacional Autonoma de Mexico found that blueberries may help fight age-related declines in rats' memories. Aging rats that were fed a blueberry-supplemented diet for four months tested as well as younger rats in their abilities to recognize objects after an hour. Aging rats fed a normal diet failed to recognize the objects. This complete deficit was fully alleviated by diet. 11/13/01
Spinach, Spirulina Help Rat Brain, Apples Help Some, Cucumbers Not at All: Two studies published 7/15/02. J Neurosciences found rats 6 weeks on spinach at 2% of chow had reversal of aging effects. Aged rats fed either spirulina-or apple-enriched diets for two weeks demonstrated improved neuron function, a suppression of inflammatory substances in the brain, and a decrease in malondialdehyde (MDA), a marker for oxidative damage. In fact, spirulina reversed the impairment in adrenergic neural function normally associated with aging. U S. Fla.
Fat: Animal Fat, Cholesterol Bad, Fish Prevents Dementia: The prospective Zutphen Elderly Study (n=476) and the Rotterdam Study (n=5,386): Rotterdam Study showed that high intakes associated with an increased risk of dementia after adjustments: total fat (RR=2.4 (95%CI: 1.1-5.2)), saturated fat (RR=1.9 (95%CI: 0.9-4.0)), and cholesterol (RR=1.7 (95%CI: 0.9-3.2)). A high fish consumption, an important source of n-3 PUFAs, reduced the risk of dementia (RR=0.4 (95%CI: 0.2-0.9)). In the Zutphen Elderly Study a high linoleic acid intake was associated with cognitive impairment (OR=1.8 (95%CI: 1.0-3.0)). A high fish consumption tended to be inversely associated with cognitive impairment and decline (RR=0.5, 95%CI: 0.2-1.2). J Nutr Health Aging 2000;4(4):202-207
Vegetarians Less Depressed?: More anxiety and depression where reported in the non-vegetarian groups in comparison with the vegetarian groups. However, there were only 80 people in the study. Puerto Rico. Bol Asoc Med P R 1998 Apr-Jun;90(4-6):58-68