Turmeric/Curcumin � clinically effective in humans after all? SLC6A15 Amino Acid Transporter


Turmeric powder, only in food, modified the SLC6A15 gene

I know that most readers of this blog want to treat autism with supplements and/or diet.
Many supplements and herbal medicines do show promise in the laboratory, when tests are conducted in vitro, but very often when tests are made in humans the results are much weaker, or just not present.  Turmeric/Curcumin is a perfect example; in the test tube it has a wide range of potent benefits, but due to low absorption into humans (bioavailability) it does not show such conclusive results in human studies.
One researcher a while back did send me a study that reviewed all the turmeric/curcumin trials and it concluded that curcumin has no beneficial effect in humans.
In modern medicine anecdotal evidence does not count. Some anecdotes are genuine, but some are coincidence and some are placebo. 

Mini trial of Turmeric at three UK Universities
There is a remarkably good medical program produced by the BBC in the UK, called Trust me I�m a Doctor, where the doctor presenters team up with universities to test practical medical hypotheses.
In one study they took 100 people to assess whether turmeric has any measurable medical benefit. They teamed up with Newcastle University, Leeds University and a clever genetic researcher at University College London (UCL).

They showed that eating turmeric in your food modified a specific gene (SLC6A15) associated with certain cancers, asthma/eczema and depression.
Taking turmeric as a supplement pill or taking a placebo pill had no effect on the gene.
The researcher at UCL was measuring the epigenetic tags attached to the genes. He showed that methylation of this gene was increased by dietary turmeric. Changing the methylation of this gene will change when it turns on/off.
Anecdotally, we know that people who eat a lot of turmeric tend to have less cancer, less asthma and less eczema.
Given that this gene is also associated with depression, you might expect big eaters of turmeric to have either less, or more, depression. Probably nobody has researched this.  

SLC6 Gene Family
It is true that asthma and eczema (atopic dermatitis) are common in people with autism, but variations in the broader SLC6 family of genes are known to affect people with ADHD, Fragile X, Tourette�s and broad autism.
SLC transporters encompass approximately 350 transporters organized into 55 families. The SLC6 family is among the largest SLC families, containing 20 genes that encode a group of highly similar transporter proteins. These proteins perform transport of amino acids and amino acid derivatives into cells. 


In humans, the SLC6 family of transporters defines one of the most clinically relevant protein groups with links to orthostatic intolerance, attention deficit hyperactivity disorder (ADHD), addiction, osmotic imbalance, X-linked mental retardation , Hartnup disorder, hyperekplexia, Tourette syndrome, schizophrenia, Parkinson disease (PD), autism  and mood disorders such as depression, anxiety, obsessive compulsive disorder (OCD), and post-traumatic stress disorder (PTSD).
This review will focus on the structure-function aspects of the mammalian SLC6 transporters, their regulation by both classical as well as emerging epigenetic/transgenerational mechanisms and what impact these properties may have on disease and the use of biomarkers to detect these proteins in disease states  

The functional impact of SLC6 transporter genetic variation.


Solute carrier 6 (SLC6) is a gene family of ion-coupled plasma membrane cotransporters, including transporters of neurotransmitters, amino acids, and osmolytes that mediate the movement of their substrates into cells to facilitate or regulate synaptic transmission, neurotransmitter recycling, metabolic function, and fluid homeostasis. Polymorphisms in transporter genes may influence expression and activity of transporters and contribute to behavior, traits, and disease. Determining the relationship between the monoamine transporters and complex psychiatric disorders has been a particular challenge that is being met by evolving approaches. Elucidating the functional consequences of and interactions among polymorphic sites is advancing our understanding of this relationship. Examining the influence of environmental influences, especially early-life events, has helped bridge the gap between genotype and phenotype. Refining phenotypes, through assessment of endophenotypes, specific behavioral tasks, medication response, and brain network properties has also improved detection of the impact of genetic variation on complex behavior and disease. 

Amino acids are very important and it is not just that you need them, but you need them in the right place at the right time.
It appears that one of the many effects of defective amino acid/derivative transport into cells is on behaviour.
Improving amino acid transmission is therefore a potential therapy to correct aberrant behaviour, including depression but likely much more. 

Conclusion
Modern clinical trials are often hugely expensive, but as the BBC keeps showing with its TV series, you can carry out very meaningful research without breaking the bank.
You would think that cancer researchers would now look at the modified versions of turmeric that claim higher bioavailability and see if these pills can also modify this cancer gene, since they can easily repeat the UCL laboratory analysis. I doubt this will happen any time soon.
It has long been known that turmeric is not well absorbed, but just one teaspoon a day added to food was enough to modify the gene.
Indians have a low incidence of cancer and a high consumption of turmeric. Turmeric should particularly limit breast cancer.

Source: https://vizhub.healthdata.org/gbd-compare/

The above chart, where blue is best, shows India does well, as do some other turmeric eating countries (South Asia and the Middle East). Clearly longevity and quality of healthcare also matter, so beware Africa. Europe, Russia, Argentina, Uraguay, Oz, NZ and North American might want to up their turmeric intake.

We can say that turmeric is a potential epigenetic therapy for at least one important gene (SLC6A15) and possibly more, because turmeric does not just affect methylation. It has several other better documented epigenetic properties. 

Epigenetic regulation, which includes changes in DNA methylation, histone modifications, and alteration in microRNA (miRNA) expression without any change in the DNA sequence, constitutes an important mechanism by which dietary components can selectively activate or inactivate gene expression. Curcumin (diferuloylmethane), a component of the golden spice Curcuma longa, commonly known as turmeric, has recently been determined to induce epigenetic changes. This review summarizes current knowledge about the effect of curcumin on the regulation of histone deacetylases, histone acetyltransferases, DNA methyltransferase I, and miRNAs. How these changes lead to modulation of gene expression is also discussed. We also discuss other nutraceuticals which exhibit similar properties. The development of curcumin for clinical use as a regulator of epigenetic changes, however, needs further investigation to determine novel and effective chemopreventive strategies, either alone or in combination with other anticancer agents, for improving cancer treatment.
Only a few reports have so far investigated the effect of curcumin on DNA methylation. Molecular docking of the interaction between curcumin and DNMT1 suggested that curcumin covalently blocks the catalytic thiolate of DNMT1 to exert its inhibitory effect on DNA methylation. However, a more recent study showed no curcumin-dependent demethylation, which suggested that curcumin has little or no pharmacologically relevant activity as a DNMT inhibitor. To clarify these contradictions, more research is urgently needed.
Given that 5-azacitidine and decitabine, two FDA-approved hypomethylating agents for treating myelodysplastic syndrome, have a demonstrated ability to sensitize cancer cells to chemotherapeutic agents, it would be worthwhile to explore whether the hypomethylation effect of curcumin can also induce cancer cell chemosensitization. Interestingly, a phase 1 trial with curcumin administered several days before docetaxel in patients with metastatic breast cancer resulted in 5 partial remissions and stable disease in 3 of 8 patients. This unexpected high response might have resulted from the clever sequential delivery of these two agents, which capitalized on and maximized curcumin�s epigenetic activity for cancer treatment.


Docetaxel is a 20 year old chemotherapy drug produced using extracts from the leaves of the European yew tree, perhaps best taken with root (rhizome) of the Asian Curcuma Longa plant. 
The main mode of therapeutic action of docetaxel is the suppression of microtubule dynamic assembly and disassembly. It exhibits cytotoxic activity on breast, colorectal, lung, ovarian, gastric, renal and prostate cancer cells.



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