Is brain damage associated with milk consumption due to the banned pesticide heptachlor or the milk sugar galactose?
Parkinson’s disease is a brain disease that affects millions of people. What causes it? However, when looking at lifestyle factors associated with Parkinson’s disease, dairy consumption is the strongest dietary factor associated with an increased risk of Parkinson’s disease. In fact, dairy products are the only food group linked to a higher risk of developing Parkinson’s. Five large prospective studies confirmed the link. This includes two Harvard groups, the Nurses’ Health Study and the Health Professionals Follow-up Study, which followed more than 100,000 people together for decades in “the largest analysis of milk and PD. [Parkinson’s disease] so far,” analyzed more than 1,000 newly diagnosed cases. All studies found a link between milk and Parkinson’s, most found a significant link—about a 50% increased risk in those who drank the most milk compared to those who drank the least, p-a value less than 0.00001, which means there is less than a 1 in 100,000 chance of getting that random. You can see this in the chart below and at 1:13 in my video, The Role Milk May Play in the Triggering of Parkinson’s Disease.
Okay, but why is there a link at all? “Despite the clear association between milk consumption” and the occurrence of Parkinson’s, “there is no reasonable explanation,” concludes one review. However, a year later, we found a clue: “Milk consumption during life and nigra neuron density at death.” What does that mean? Parkinson’s is primarily caused by the loss of a certain type of nerve cell in a sensitive part of the brain, and symptoms begin to appear when most of these neurons have died. So another study looked at how much milk people drank in their 40s, 50s, and 60s, then examined their brains at autopsy and counted how many of those sensitive neurons they had left. In all quadrants, the density of neurons was highest “in those who did not eat milk and lowest in those who ate a lot of milk.” Even after excluding cases of Parkinson’s, those who drank two cups (473 mL) of milk a day had up to 40% fewer nerve cells in multiple quadrants of that sensitive brain region. What is in milk that might destroy brain cells? Among people who drank a lot of milk, residues of the pesticide “heptachlor epoxide were found in 9 out of 10 brains.” Therefore, perhaps the finding of pesticide residues more often in the brains of those who drink a lot of milk could explain how milk may be a cause-and-effect link to the risk of Parkinson’s disease.
Now, that’s not the only possible explanation. In one of my videos, I talked about how meat contains that neurotoxic alpha-synuclein protein. However, dairy products may contain trace amounts, but we have no guarantee of that. Is milk sugar “galactose the missing link?” Galactose is what the lactose in milk breaks down into when it’s in the body. It is also what is used to induce aging—to cause experimental aging—in the brain. When you drink it, galactose is taken up by your brain within a few hours, and at doses above 100 mg/kg, it appears that galactose can cause pathological changes in brain cells, similar to those seen in Parkinson’s disease. This amount can be “met and exceeded” by simply drinking two glasses (473 mL) of milk (the main dietary source of galactose) each day. And of all your brain cells, those dopaminergic neurons – the ones you need to protect to prevent Parkinson’s – may be more vulnerable to damage caused by galactose because they are more vulnerable to oxidative stress.
Galactose may also explain the results linking milk consumption to higher mortality rates. You might think, “Well, full butterfat shortens people’s lives,” but higher mortality rates have been observed for people with high milk consumption regardless of the amount of milk fat. Skim milk may not contain fat, but it does contain lactose.
Can’t drink lactose-free milk, like Lactaid? That has the enzyme lactase added to make milk lactose-free. But it just breaks down the lactose into galactose in the box rather than in your gut, so you’re still eating the same amount of galactose. Perhaps not surprisingly, more milk consumed during life may be associated with greater rates of cognitive decline. Remember, researchers use galactose to create brain aging in the laboratory. Galactose, a metabolic derivative of lactose, has been widely used in animal models to “simulate cognitive aging” through oxidative stress. Compared to those who say they “almost never” drink milk, those who drink more than one glass (237 mL) a day appear to be at greater risk of global cognitive decline.
Doctor’s Note
Here’s a video of the meat I mentioned: The Role of Meat May Play in the Triggering of Parkinson’s Disease.
You may remember that I have reviewed this before Could Lactose Explain the Link of Milk and Parkinson’s Disease?. Uric acid may also be a competitor Parkinson’s Disease and the Uric Acid Sweet Spot.
For more on Parkinson’s disease, see the related posts below.
