Gwyneth Paltrow faced scrutiny after a guest writer for her health website claimed a protein in cucumbers could lead to Alzheimer's.
Goop is ridiculed for promoting expensive lifestyle products and many questionable health theories, reports Daily Mail.
In a recent post, Goop's Dr Steven Gundry, a heart surgeon and cardiologist specialist from California, said he found a link between memory loss and lectins, found in cucumbers, tomatoes and whole grains.
He said such food could even lead eaters to develop dementia.
The article sparked a flurry on Twitter, with readers gleefully making fun of the "ridiculous" suggestion.
But it seems this time Gwyneth may have the last laugh.
Nutritionists and doctors who normally criticize Goop have admitted to Daily Mail Online that there is evidence to show lectins are harmful to the gut and could cause a host of issues - and possibly memory loss.
England's Dr Tom Greenfield, who examines the effects of lectins on different blood types, said the protein can 'absolutely' play a role in brain disorders.
He said the protein impacts people differently and the damage they can cause really comes down to a person's genetics.
He said: "There is a specific link to blood types. You can't say 'avoid all lectins' because some might be good for people and bad for others.
"Lectins can change your body, immune system and blood levels. They can block insulin receptors and over time this can affect blood vessels, even in the brain.
"So if blood vessels aren't working, it will cause damage to the brain."
Dr David Jockers said lectins have been shown to block nutrient absorption, which leads to problems.
He said: "In general they are stressful on the body. Lectins have an affinity to latch on to leptin and insulin receptors."
He added: "I don't think lectins are a major cause of dementia and Alzheimer's, but I could see how they could be a factor."
Nikki Ostrower, holistic nutritionist and founder of NAO Nutrition & Wellness, said the idea of avoiding foods with lectins is common among experts but lesser-known to the public.
She said: "Before pesticides, plants developed their own way of fighting off threats. When we consume these foods raw we are ingesting that natural repellent.
"They are anti-nutrient, can cause leaky gut issues and could even be responsible for autoimmune diseases."
Lectins are found in a variety of food that are deemed healthy, such as tomatoes, peppers, cucumbers, soy, grains, sprouted grains, beans and some diary products.
Ostrower said it may be unrealistic for some people to cut out all of these foods entirely, so she recommends cooking them.
She said: "If you cook them, you are lightening the burden of the harm. Also, soaking and fermenting will help."
Nutritionist Mary Jane Detroyer said lectins are associated with Alzheimer placques but said there needs to be much more research done on the topic.
Dr Gundry clearly makes the connection to lectins and memory loss in his article.
Dr Gundry wrote: "Some lectins resemble proteins in the body, while others are designed to look like compounds that the body considers harmful, such as lipopolysaccharides - which are fragments of bacteria that are constantly produced as bacteria divide and die in your gut.
"Lectins resemblance to other proteins in the body and LPSs can cause the immune system to attack, leading to inflammatory reactions in the body, and health issues like leaky gut, brain fog, neuropathy, and autoimmune disease."
In the past few years, experts have been investigating the notion that diseases affecting the brain begin in the gut.
The American Academy of Neurology published a study in April that suggested Parkinson's disease started in the stomach.
It found the neurodegenerative disease appeared to be triggered by a protein in the stomach and spreads to the brain via the vagus nerve.
The nerve extends from the abdomen to the brainstem and controls unconscious body processes like heart rate and food digestion.
Patients who underwent surgery to remove the trunk of the nerve were 40 percent less likely to develop Parkinson's than those who hadn't.
With our gut health and overall health believed to be strongly linked, intense physiological stress could therefore raise the risks of many types of illnesses.
Long periods of intense exercise can change the composition of your gut bacteria and lead to leaky guy syndrome.
The research looked at soldiers taking part in an intensive training program and found that pro-longed exercise caused the protective barrier in their guts to become permeable, and could let harmful substances leak into the bloodstream.
The Perelman School of Medicine at the University of Pennsylvania is part of a growing swell of research showing links between the gut and the brain.
Their researchers found that bacteria in the gut microbiome could be the cause of a crippling hard-to-treat brain disease called cerebral cavernous malformations (CCMs).