Category Archives: Diet/Obesity
I met a woman over the weekend who told me that she had been diagnosed with early onset Parkinson’s disease (PD) after she learned that I studied the effects of pesticides on brain development. I felt sympathetic towards her because she is only 39 years old and is on several medications and recently went through surgery for deep brain stimulation (DBS) to try to minimize the effects of the disorder. She told me that before people are aware she has PD she had been called “mumbles” because she has a hard time enunciating her words. She also told me the meds that she is on for the disorder cause her to act differently than she used to. Despite all she has been through, she remains positive and upbeat about her situation which really impressed me.
Parkinson’s disease is a disorder in which areas of the brain involved in dopamine release start to degenerate. Dopamine is a neurotransmitter needed for motor control. Over time, this loss causes movement problems, tremors, and difficulty walking and talking. While there are medications given to patients with this disorder, they can only treat it and slow down its progress. Deep brain stimulation is an effective treatment for PD, yet is highly invasive with a pacemaker inserted into the brain so the patient can use a remote to inactivate or stimulate areas of the brain depending on the symptoms of the patient.
Currently, the causes of Parkinson’s disease are unknown, albeit much attention is on the role of environmental toxicants. Roughly 5% of PD cases are solely from genetic mutations. Even though there is no specific cause of PD, individuals that are ‘genetically predisposed’ are at a higher risk for the disorder, especially in conjuction with environmental toxicant exposure. Earlier studies reported that certain pesticides disrupt locomotor activity and alter dopaminergic neurons and dopamine release from those neurons. Just this month, scientists from University of California San Diego published a study indicating that the herbicide Paraquat and the fungicide Maneb affect the growth of new neurons in the adult brain and the expression of genes involved in the formation of new neurons (using mice). Both Paraquat and Maneb have been found in a large number of non-organic foods. Maneb was banned since 2010, but was in use since the mid-1900s. Paraquat is one of the most used pesticides, since 1955, even though it is extremely toxic. Farm workers exposed to these pesticides have an extremely high risk of getting Parkinson’s disease.
I’ve written about pesticides before, but it doesn’t hurt to reiterate to make you aware of what you are putting in your body. Even though you probably aren’t a farmer exposed to high levels of pesticides, studies show that eating organic foods drastically lowers the levels of pesticide metabolites in the body. We all know that eating organic is more expensive, but it might be worth giving up some other non essentials to invest in our health. With the abundance of research on the harmful effects of pesticides, we can’t ignore the facts that they are poisoning our bodies and our environment. At the very least, take a look at the ” The dirty dozen ” foods with the highest amount of pesticide residues and try to incorporate those into your diet. I think it’s time that being pro-organic shouldn’t be the minority anymore!
Desplats, PA. et al. Combined exposure to Maneb and Paraquat alters transcriptional regulation of neurogenesis-related genes in mice models of Parkinson’s disease. Mol Neurodegener. Sep 2012 28;7(1):49.
Arkury TA et al. “Pesticide Urinary Metabolite Levels of Children in Eastern North Carolina Farmworker Households.” Environ Health Perspect Aug 2007;115(8).
Did you ever say to yourself “I will just have a small piece of ________ (cheesecake, ice cream, cake… fill in the blank!)” and end up eating way more than you wanted to? Did you ever notice that when you “fall off the wagon” of eating healthy, it’s harder to get back to eating healthy than it is to give into junk food?
A recent review article in the journal Frontiers in Neuroendocrinology by Johan Alsio, Ph.D. and others illustrates how much our bodies are made for holding onto fat by way of brain changes, variations in hormone levels, and molecular adaptations during overeating.
In our society, we tend to eat not only from hunger, but from food cravings even at the risk of gaining weight, developing diabetes, and increasing our cholesterol levels – if left unchecked making us susceptible to disorders and disease. So, why can’t we stop the bad cycle of indulging too much?
Apparently the link between drug addiction and food addiction is quite closer than we might think because both activate pathways in the brain that affect levels of the neurotransmitter dopamine (aka – the reward system). Get this: the same changes are seen in this pathway in both obese individuals and those that are addicted to cocaine, meth, and heroin! The higher preference there is for sugar correlated to a bigger preference for alcohol, cocaine and speed in rodent models.
Food also acts like a drug in that the more you are exposed to higher fat and higher sugar foods, the more your body will crave them (a ‘feed-forward’ system – ironic, right?). The higher your weight, the bigger the craving for high fat and high sugar foods. So you might wonder what happens if we actively choose to eat super healthy and stay away from junk (easier said than done considering we have pizza, burgers, and ice cream waiting at the back door). Even if you can withstand the higher cravings during ‘dieting’ – this usually leads to higher and longer periods of cravings, making it much easier to give in. Sometimes that salad just doesn’t do it for us, but those steak burritos across the street…..they just sound so yummy In studies done with animals, the longer time period of abstinence from high fat and high sugar foods caused their sugar cravings to increase, they had higher anxiety levels, they were more susceptible and higher tendency to show food-seeking behavior – you can see how this can become a never-ending cycle – like Lindsay Lohan’s frequent visits to rehab. These effects create the yo-yo dieting that is common in our society.
Similar to drug use, there are also withdrawal symptoms after abstaining from high fat/high sugar foods – emotionalism, anxiety, cravings (the neurological symptoms), but also physical symptoms like teeth chattering and tremors (shown in rodents). They mental and physical symptoms are attributed to changes that happen in the brain after exposure to these foods. One that I mentioned before: dopamine levels change and the body’s response to it are altered, but also changes in the receptors for endocannabinoids (think, marijuana), and changes in receptors for opioids. The more we eat junk food, the more we want it – risking health issues and obesity (and get this: the more obese a person is, the less likely they are to become addicted to drugs, because food fills that void). The changes that happen in the brain seem permanent; this is why many people gain the weight back that they lost years ago (so relapsing to bad behaviors doesn’t just happen after short-term healthy eating).
Evolutionarily, seeking out high fat and high sugar foods was crucial in times when food wasn’t readily available… so the problem is that while we have food everywhere now, our bodies haven’t really caught up.
Questions to think about:
1) Can we override the signals in the brain that tell us to seek more food?
2) How well does cognitive behavioral therapy work for overweight and obese patients?
3) To what extent can exercise reverse changes that happen in the brain and body that increase the drive to eat?