Depression can affect even the most stable of us at any time without warning, and in many cases, seemingly without cause. If you're regularly affected by random bouts of depression or just the blues then there's a very good chance that it's being created by what you're eating rather than emotional instability or stress.
Whereas you might think that if you were to have any form of food sensitivity it would cause stomach upsets along with its other symptoms, in fact that's not always the case. Wheat, for example, can cause dark depression (usually within an hour or two of consumption) back and pelvis pains, cause old muscle and bone injuries to flare up in, headaches, sensitivity to other foods and a weakened reaction to stress. Potato starch (or more accurately the neurotoxins solanine and chaconine in potatoes) again causes depression, and a wealth of other non-gastric symptoms, including being implicated in some forms of birth defects, so varied that the last thing you may do is pin them on something you've eaten. The depth of symptoms listed below may vary, depending on your current stress-levels and the consumption of other foods in conjunction with the offending food.
Dairy: Symptoms can occur after just a small amount of lactose/lactase, casein, or whey has been eaten, usually within about an hour of consumption, lasting up to two days. Causes: depression, stomach upsets, nasal blockages, chest problems through an increase in mucus production, joint aches, halitosis, light sensitivity, fatigue.
Wheat: Symptoms can occur after just a small amount of gluten has been eaten, usually within about an hour of consumption, lasting up to a week. They include depression, stomach upsets, nasal blockages, chest problems, joint aches, abdominal and intestinal pains, the reoccurrence of pain from old injuries (including back pain).
Potato Starch: Potato starch is used in a vast range of foods, so is very hard to avoid. Its production is amongst the largest industries in the world. The potato starch industry consumes around 1,000m3 of natural gas per hour and discharges in wastewater the equivalent of 2.9 million people’s wastewater.
Solanine can cause serious illness at concentrations of >280 mg kg-1 f.w. Symptoms generally occur after 8-12 hours after ingestion and can include gastrointestinal disturbances and neurological disorders. Mild symptoms can include headaches, dizziness, abdominal pain, nausea, vomiting and diarrhoea. Other symptoms can include: fever, restlessness, drowsiness and mental confusion, trembling and hallucination, sleep disorders, loss of libido, clumsiness, depression, anxiety, coma, delerium, and a variety of pains in ribs and pelvis, coldness, anxiety, lack of sense of warmth and empathy for other humans, and visual effects. Make no mistake, the psychological effects of solanine are broad and very hard to categorise simply here - and they can last years. - but because the symptoms are common to a whole host of other ailments, mistaken diagnoses can occur.
Not all symptoms may be present in any individual case of solanine poisoning. The range of symptoms experienced can be more varied and extensive after regular exposure to less than toxic levels than through direct poisoning with toxic levels.
Do you have food sensitivities?
If you have any long-lasting physical or mental sensations you're worried about that your GP can't seem to sort out, it's well worth checking to see if you are reacting adversely to one of the above, simply by excluding them from your diet for around a week and seeing how you feel. For me personally, the effects of wheat last around 6 days, potato starch for about four and a half days, and dairy about a day and a half. If you've managed to totally exclude them from your diet and don't feel better within that week, the chances are that you aren't sensitive to them.
However, it does require a lot of cautious label-reading of every food you buy to remove them from your diet; lactose and whey powder (the worst causes of dairy reactions) and gluten are in almost every food you can buy. But, even though this is the case and you may have to severely change your diet to compensate for their removal, the increase in physical and mental well-being you will get in return is invaluable.
Despite many, many visits to GPs over the last 15 years, it wasn't until a year ago that I discovered that I too was suffering from ongoing solanine poisoning. I'm a vegan, and potatoes have always played a key role in my diet, with my consumption perhaps up to 8 oz a day (boiled, chipped or baked), plus a daily bag of baked potato chips. The particular brand of chips I ate was of a kind reconstituted from potato starch and flakes - a common production method nowadays - and was probably responsible for pushing me over into more intense symptoms. It was very hard to function most days because of the pain and discomfort, but really it was the psychological symptoms that were most worrying. Reality felt flat, I felt devoid of emotions to some degree, and wanted little more than to be left alone while I just sat and stared into space. I was always cold, with white face and hands for much of the time, and dark rings and bags under my eyes - a very good indicator of food intolerance of some kind.
Although statistically we can show that reported cases of food sensitivities are certainly on the increase, medical science is still reticent to regard them as real, treatable illnesses. Wheat intolerance (Celiac disease), for example, is of course a recognised condition, whereas mere wheat sensitivity isn't, and even though its symptoms can be quite extreme and equally debilitating, you're unlikely to get much interest in your condition from your GP.
It's only over the last 15 years in the UK that GP's have recognised dairy sensitivity as a real illness, even though most adult humans show some adverse reaction dairy and it being long known that adults are unable to process the proteins within it (lactose and casein). There seems to be a 'head in the sand' attitude towards most forms of food sensitivity, possibly because our already over-burdened health systems would be unable to cope if the magnitude were truly known. It would also cause massive problems in food production industries, with a minimum of 50% of the population having to come off either dairy, gluten or potato starch.
Potato Starch, the modern peril
Whereas there are many good sites and articles on both gluten and dairy sensitivities, you'll find very little on the perils of potato starch and its glycoalkaloids, solanine and chaconine. Solanine is a dangerous neurotoxin that attacks brain functions, and therefore not just something that may give you an upset stomach for a few hours. Potatoes, apples, bell peppers and tomatoes are all members of the Deadly Nightshade family, and each contains levels of solanine.
All potato plants contain solanine (and a similar glycoalkaloid, chaconine) in their leaves, stems and the potatoes themselves, concentrated mainly in the outer quarter of an inch from their skins. Solanine is the potato's natural form of defence and, should it be attacked by insects or damaged by light or bruising, the solanine builds up at the site of the damage to protect the potato, showing as the familiar greening of the potato fruit and skin. However, the solanine is present in the potato all the time, green or not, so if you have a sensitivity to it, not eating the skins or greened potatos isn't going to stop you ingesting solanine, and nor is cutting off a greened section. A greened potato is at the final stage of solanine proliferation, and it is therefore not truly safe to eat it at all.
Although the natural presence of solanine in healthy potatoes that are well-handled, stored and displayed is usually within acceptable bounds, there are no regulations concerning safe production of potatoes or potato starch, only guidance which producers may or may not follow. Food manufacturers and retailers will tend to use potatoes and potato starch from the cheapest sources, not necessarily the safest.
On the increase
With modern production methods the solanine content in potatoes is much higher than it was say, 30 years ago - and solanine may even account for the global increase in varieties of cancer over that same period. Bearing in mind that the amount of solanine in a single potato can be increased ten-fold by being displayed openly in daylight, it's easy to point out the problems in current potato production:
1) Potatoes were initially picked then stored in barns under earth and straw to stop them rooting (and producing solanine at the sites of these new roots). Nowadays potatoes are picked and stored in daylight in open heaps for weeks at a time.
2) Potatoes were sold at one time in hemp or paper sacks that were near impervious to light, currently many are sold (either at a trade or retail level) in transparent plastic sacks. At retail in particular, potatoes are routinely displayed under lights, with no concern either for light or bruising damage that will cause a rapid increase in solanine content.
3) Many cafes and restaurants now buy pre-peeled and/or chipped potatoes, which are stored in water in transparent plastic sacks. The bags of potatoes may be stored in daylight for quite long periods, both at the supplier's warehouse and in the user's pantry. If four hours of daylight quadruples solanine levels in a potato with its skin in place, what would the levels be in a peeled potato stored incorrectly for a day or more?
Case of solanine poisoning, from: http://lib.bioinfo.pl/meid:135164/pmid
Seventy-eight junior schoolboys in Great Britain became ill from solanine poisoning 7 to 9 h after eating two small boiled peeled potatoes each (weight of potatoes not given) as part of their lunch, and 17 were admitted to hospital. Symptoms included vomiting, diarrhoea, and general abdominal pain. Most of the boys developed a fever, suffered from headache, dizziness, mental confusion, hallucinations and their vision was affected. Three boys were comatose and stuporose on admission, with peripheral circulatory collapse. All were discharged 6-11 days following admission, and 4-5 weeks later there were no sequelae. Tests for the presence of biocides, such as nicotine, organophosphorus or organochloride pesticides were negative. Six days after eating the meal, plasma pseudocholinesterase levels in 10 out of 17 schoolboys was subnormal
(about 25% below the normal range for this age group). Red blood cell cholinesterase levels were normal. The source of toxic potatoes was traced to a bag of old potatoes that had been condemned for consumption because of their appearance, but that had inadvertently been cooked (peeling of the potatoes had been done by an automatic peeling machine)...Because of the small margin of safety between normal potatoes and toxic potatoes, the authors speculated that in toxic potatoes other toxic steroids besides glycoalkaloids may be synthesized, such as sapogenins and saponins, which might enhance the toxicity of solanine alkaloids by promoting gastro-intestinal absorption or other means (McMillan & Thompson, 1979).
The Committee considered that, despite the long history of human consumption of plants containing glycoalkaloids, the available epidemiological and experimental data from human and laboratory animal studies did not permit the determination of a safe level of intake. The Committee recognized that the development of empirical data to support such a level would require considerable effort..."
So, with proper handling, the chances of potatoes reaching acute toxicity can be reduced. However, as illustrated above, potatoes nowadays are neither handled correctly nor sold in the packaging they should be to prevent solanine accumulating to dangerous levels. With no legislation to prevent potatoes being produced or retailed as they are you'd be very hard-pushed to find anyone in the entire chain of production who is even interested in checking for glycoalkloids. What then becomes of those who have potatoes or potato products every day, who will develop underlying solanine poisoning and various knock-on illnesses without realising it? What GP would ever check for it? Be in no doubt, solanine is a powerful poison, and anyone who regularly has say, salad potatoes (always eaten in their entirety, including their skins), or a packet of baked potato chips, or even some forms of rice crackers, will be at risk from its effects.
Excerpts from The National Toxicology Program report on solanine and chaconine in potatoes: Executive Summary Chaconine and Solanine: 6.0 through 8.0 - National Toxicology Program
Cooking to remove glycoalkaloids: Boiling is not effective in decreasing the concentrations of a-chaconine and a-solanine in potatoes (Takagi et al., 1990). Microwaving reduced the alkaloid content by 15%, and deep frying showed mixed results depending on cooking temperature. The authors noted that the critical temperature for the decomposition of both alkaloids in cooked potatoes was 170oC. Freeze drying and dehydration of potatoes reduced the glycoalkaloid content either slightly or not at all (Brain and Turner, 1971; Zaletskaya et al., 1977; both cited by Morris and Lee, 1984).
Thirty to eighty percent of the glycoalkaloids in the potato tuber are found in the outer layers (Meyer, 1895; Bomer and Mattis, 1924; Griebel, 1924; Wolf and Duggar, 1946; all cited by Maga, 1980). Thus, peeling generally reduces glycoalkaloid intake (Lagolo et al., 1991; cited by Hoskins, 1994). However, a study by Mondy and Gosselin (1988; cited by Beier, 1990) concluded that peeling potatoes prior to cooking did not decrease the glycoalkaloid content.
Fried potato peels are a source of large quantities of a-chaconine and a-solanine; one study indicated that fried potato peels had a-chaconine plus a-solanine levels of 1.4 to 1.5 mg/g potato peel (Bushway and Ponnampalam, 1981), which is seven times the recommended upper safety limit (0.2 mg/g potato) (Beier, 1990). Another study found that combined a-chaconine and a-solanine levels in baked or fried peels of commercial potato varieties ranged from 0.02 to 1.1 mg/g potato peel and 0.03 to 1.6 mg/g potato peel, respectively (Bushway et al., 1983). Additionally, the concentration of glycoalkaloids in commercial potato chips varies between 0.1 and 0.7 mg/g of chips (Sizer et al., 1980). (edit: Three to six milligrams of solanine per kilogram of body mass can be fatal.)
Solanine implicated in birth defects: http://www.pubmedcen...69&blobtype=pdf