Watching TV means impaired health and intelligence??

Sedentary behaviors and limited physical activity are known to have detrimental effects on health. Now they are also associated with decreased cognitive performance.

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Idleness is increasing at alarming rates as our previous physically demanding life is replaced with desk jobs, watching TV and driving, in which we spend about 6h, 4h and 1h per day respectively. On average, 80% of American adults spend a disturbing 3.5h of their day in front of the TV and 70% of their waking hours sitting.

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Physical health

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The effects of these habits are well-known: cardiovascular disease, type 2 diabetes, chronic obstructive pulmonary disease, influenza, pneumonia, liver disease, suicide, obesity, Parkinson disease and certain cancers. These diseases are so common that they are responsible for more than the 63% of all deaths in the US and they are all, except for Parkinson and liver disease, listed on the top 10 leading causes of demise. These effects were seen on average individuals aged 50-71 years, initially free of chronic conditions that for more than 14 years watched TV for as little as 2 hours. The study also showed that people who watch TV 3-4h/day are 15% more prone to die from any cause than those who spend less than 1h/day. Beware of viewing TV more than 7/day because your death risk is 47% higher.

Mental health

Exercising will not only help you elude those fatal diseases and increase your lifespan, but it will also improve your mental health by reducing tiredness, anxiety, bad mood, weight gain and depression; improving self-esteem, sleep, mental alertness and assertiveness; combating alcoholism and drug abuse; and increasing stamina, energy levels and sexual satisfaction. A substantial number of studies have shown that exercising increases positive affect (PA) while decreasing negative affect (NA). PA is an attribute that describes how sentient beings react to positive emotions and interact with their ecosystem. It is related to feelings of confidence, enthusiasm and alertness, whereas NA is characterized by sadness, lethargy and anguish.

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Cognitive function

All these data are nothing new but the correlation of exercise and mental performance is something of a novelty.

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In 2003, several studies proved that acute sessions of exercise ameliorates cognitive function in a plethora of tasks like simple reaction time (RT) or response inhibition to creative thinking. The former refers to the required time to respond in a predetermined way to a defined stimulus while the second one relates to the suppression of ideas that were not considered appropriate in the given context. One of these studies found that a 30 min run promotes the allocation of attention and memory, improving executive tasks such as working memory, inhibitory processes or multitasking. Another investigation concluded that individuals who exercise during their mid-30s have better memory latter in life. Results from a study done in 2006 showed how aerobic exercise three times a week for six months increases both gray-and white-matter compared to just stretching.


A recent study has been one of the firsts to demonstrate how watching TV and physical inactivity should be reduced to prevent cognitive aging. The researchers analyzed data from 3247 adults, both black and white aging from 18 to 30, who participated in the Coronary Artery Risk Development in Young Adults (CARDIA) Study. Over 25 years the participants were asked more than 3 times to complete some questionnaires about how much exercise they performed and the amount of TV they viewed. At the end of the trial, contestants did three neuropsychological tests:

• The Digit Symbol Substitution Test (DSST) assesses your memory and processing speed and it is sensitive to brain injury, dementia and depression. It consists of 9 digit symbols, each one paired with a specific number. What the subjects must do is write down the corresponding symbol under each digit as quickly as possible within the time given.

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• The Stroop test measures executive functioning, attention and your ability to block distractions. In the test, the participants are shown written name colors in different ink colors (Blue Orange) and they are asked to name the ink color. 
• The Rey Auditory Verbal Learning Test (RAVLT) evaluates short-term auditory-verbal memory, including aspects like rate of learning, assimilation strategies or retention of information. Participants are asked to memorize a list of 15 unrelated words and repeat it 5 times with 30 min of rest in between each time. 

The results showed that those who spent more hours watching TV and were mostly inactive had poorer cognitive performance in the Digit Symbol Substitution Test and the Stroop Test but not in the Rey Auditory Verbal Learning Test. Low physical activity was strongly correlated to poor performance in the Digit Symbol Substitution Test while inactive people who watched a lot of TV performed 2 times worse than active people who did not spend as much time in front of the TV. In conclusion, too much sitting and too much TV probably leads to slow processing speed and impaired executive function (apart from all the horrendous health & mental effects already mentioned).

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Conclusion

All told, the evidence shows that exercise is an effective and low-cost way to significantly improve your quality of life in all areas of health: mental, physical and cognitive. There are enough reasons already to start working out. Sitting around all day will only make your life miserable. It is as simple as throwing on some sneakers and going for a light jog, weightlifting or signing up for a dance class. The possibilities and the reasons to do it are endless, but if you do not commit yourself to doing it, it does not matter how much exercise is praised, you will not do it.

''Health experts often remark that if exercise came in pill form it would be the most sought-after drug on the market.''

References and recommended reading

Ellies, M. (2015, October 28). TV viewing linked to increased risk of death from major causes. Retrieved December 29, 2015, from http://www.medicalnewstoday.com/articles/301693.php

Hogan, C., Mata, J., & Carstensen, L. (2013, September 10). Exercise Holds Immediate Benefits for Affect and Cognition in Younger and Older Adults. Retrieved December 29, 2015, from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3768113/

Hoang, T. et al. (2015, December 2). Effect of Physical Activity and TV Viewing on Cognitive Function. Retrieved December 30, 2015, from http://archpsyc.jamanetwork.com/article.aspx?articleid=2471270

Keadle, S. et al. (2015, December 1). Causes of Death Associated With Prolonged TV Viewing: NIH-AARP Diet and Health Study. Retrieved December 29, 2015, from http://www.ncbi.nlm.nih.gov/pubmed/26215832

Newman, T. (2015, December 2). Watching TV might slow your brain. Retrieved December 30, 2015, from http://www.medicalnewstoday.com/articles/303433.php

Nichols, H. (2015, September 21). The top 10 leading causes of death in the US. Retrieved December 29, 2015, from http://www.medicalnewstoday.com/articles/282929.php

Owen, N., Sparling, P., Healy, G., Dunstan, D., & Matthews, C. (2010, December 1). Sedentary Behavior: Emerging Evidence for a New Health Risk. Retrieved December 29, 2015, from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2996155/

Sharma, A., Madaan, V., & Petty, F. (2006). Exercise for Mental Health. Retrieved December 29, 2015, from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1470658/

Taylor, C., Sallis, J., & Needle, R. (1985, April 1). The relation of physical activity and exercise to mental health. Retrieved December 29, 2015, from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1424736/

Are potatoes deadly poisonous?!

Potatoes already have a well-deserved reputation as a fattening food but, are they also toxic?

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It is no surprise the fact that potatoes are associated with overeating, diabetes, obesity and heart disease1 given their high glycemic load. This means that they spike your blood sugar and insulin to rapidly plunge it down, making you feel hungry just after eating. What is not so well-known is that their glycoalkaloid content can be extremely harmful and acutely toxic to humans.

Glyco... what??

Glycoalkaloids are a natural-occurring pesticide that some plants produce in order to protect themselves when attacked by fungi, viruses, bacteria or insects. There are several types but the main ones found in potatoes are a-solanine and a-chaconine. There are two mechanisms by which they impair your health:

Firstly, they disrupt your epithelial barrier as they breach your cells by attaching to their cholesterol membranes. This could be detrimental to your mucosal immune system and your intestine, worsening or/and leading to conditions such as inflammatory bowel disease (IBD).^2,3

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Secondly, they are neurotoxins that hinder your body's capacity to regulate acetylcholine. This is a crucial neurotransmitter that sends nerve impulses from motor neurons to skeletal muscles activating muscle action. Glycoalkaloids stop the enzyme cholinesterase from breaking down acetylcholine, leading to an accumulation of the neurotransmitter and an overstimulation of the cells. As a result, you get a plethora of unpleasant symptoms which include⁴:

• Convulsions
• Delirium
• Diarrhoea
• Dilated pupils
• Fever
• Hallucinations
• Headache
• Loss of sensation
• Hypothermia
• Paralysis
• Shock
• Slow pulse
• Slowed breathing
• Abdominal pain
• Vision changes
• Vomiting
• Nausea
• Fatigue
• Death

Not only are glycoalkaloids responsible for acute toxicities but they can also accumulate in body tissues, especially in the liver, kidneys, heart, lungs, and brain.

In spite of the detrimental effects this chemical has, the oral toxicity is relatively low because of their poor absorption. Provided you have a healthy gastrointestinal tract, the solanine will be eliminated through the urine and faeces within 12 hours while your gut microbiome detoxifies your system by converting the toxin into solanidine, a less harmful compound⁶.

Food safety

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Human studies have shown that even 1mg of glycoalkaloid per kg of body weight can be noxious whereas 3 mg/kg might be deadly. The safety limit for glycoalkaloid content is about 20 mg per 100 g (<0.25Ib.) of potato. The peel (3 to >100mg/100g) contains 3 to 10 times more glycoalkaloids than the flesh (0.10 to 4.50 mg/100g).  Therefore, if you are going to consume potatoes you can dramatically reduce the toxic content just by peeling it. Avoid by all means eating the sprouts, any green area or unripe potatoes as they contain hazardously high amounts of the toxin.

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Storage conditions, namely light and heat, influence solanine concentrations. Try to keep them in a dark and cool place as light increases the synthesis of solanine by 20% , while temperature can do the same (at 24°C/75°F the rate of formation is 2 times greater than at 7°C/45°F).⁵

Unfortunately, the toxic content is not significantly lowered by any means of cooking. In fact, studies have shown that frying concentrates glycoalkaloids.³

Other related foods⁷

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Potatoes are part of the Nightshade (Solanaceae) Family which were not considered fit for human consumption before the 1800's given the toxicity of some varieties like the atropa belladonna (deadly nightshade). Other members of this family include tomatoes and eggplant.

Are they also poisonous? Not really or, at least, not as much:

Tomato glycoalkaloid levels drop drastically when ripen going from around 50 mg/100g in green tomatoes to about 0.5mg/100g in red tomatoes, making potatoes 20 times more toxic. There has not been conducted any human study, but the median lethal dose in rodents is 500mg per kg of body weight.

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Eggplants are considerably safer than potatoes as their solanine content goes from 1 to 2mg/100g. As with the tomatoes, I do not know about any human study but, in rodents, the median lethal dose is 1.75 mg per kg of body weight.

Nightshade sensitivity is a whole other topic that I will address in a forthcoming post.

References and recommended readings

1. "The Problem with Potatoes." The Nutrition Source. Harvard T.H. Chan School of Public Health, 24 Jan. 2014. Web.

2. Iablokov V, Sydora BC, Foshaug R, Meddings J, Driedger D, Churchill T, and Fedorak RN. "Naturally Occurring Glycoalkaloids in Potatoes Aggravate Intestinal Inflammation in Two Mouse Models of Inflammatory Bowel Disease." National Center for Biotechnology Information. U.S. National Library of Medicine, Nov. 2010. Web.

3. Patel B, Schutte R, Sporns P, Doyle J, Jewel L, and Fedorak RN. "Potato Glycoalkaloids Adversely Affect Intestinal Permeability and Aggravate Inflammatory Bowel Disease." National Center for Biotechnology Information. U.S. National Library of Medicine, Sept. 2002. Web.

4. "Potato Plant Poisoning - Green Tubers and Sprouts: MedlinePlus Medical Encyclopedia." Medline Plus. U.S. National Library of Medicine, 21 Oct. 2013. Web.

5. Cantwell, Marita. "A Review of Important Facts about Potato Glycoalkaloids." Agriculture and Natural Resources. University of California, Aug. 1996. Web.

6. Montario, Andrew. "Potato Glycoalkaloid Toxicity: Solanine." Safe Spectrum Lighting. Cornell University. Web.

7. Ede, Georgia. "How Deadly Are Nightshades?" Diagnosis: Diet. 6 Jan. 2013. Web.