The topic of insulin resistance (IR) in PwP is not often discussed. Has your MDS or neurologist ever tested you for IR?
It is estimated that two thirds of people with PD who are not diabetic, have IR and very likely are not even aware they have IR as discussed here :
parkinson.org/blog/science-....
Here are some relevant quotes from the article :
' This study suggests that nearly two thirds of non-diabetic people with PD may be insulin resistant, despite having normal blood sugar, and in some cases, despite being lean. Thus, the big take-away from this study is that people with PD may want to have a more sensitive insulin test conducted, such as the HOMA-IR, to see if they have undiagnosed insulin resistance. There are several other IR tests as well. Which of these tests, or combinations thereof, might be best to evaluate a person’s IR is something to be discussed with one’s health care provider. '
' Another important take-away (although not specifically addressed in the Hogg et al. (2018) study), is that there are an increasing number of studies suggesting that IR negatively impacts dopamine functioning in the brain. Parkinson's symptoms, including tremors, stiffness, and slowness of movement, are caused by a lack of dopamine in the brain. This is particularly noteworthy for two reasons: One, the cornerstone of therapy for PD is the drug levodopa (also called L-dopa). Levodopa works by converting into dopamine and replenishing the brain's reduced supply; straight dopamine has difficulty crossing the blood/brain barrier. Two, IR is thought to precede the development of T2D by 10 to 15 years. Thus, having advanced notice of possible IR has great value, as IR is usually reversible. And while the jury is still out as to whether – and to what extent – having IR increases one’s risk for developing PD, taking proactive steps to mitigate one’s risk for developing T2D has profound long and short-term health benefits. '
ncbi.nlm.nih.gov/books/NBK5...
The list below is from the above article link.
So even if you don't have diabetes and you have a lean body, you can still be insulin resistant and this can affect PwP and people in general, negatively. IR can cause any of the following :
1. Hyperglycemia
2. Hypertension
3. Dyslipidemia (Elevated cholesterol and triglycerides)
4. Visceral Adiposity
5. Hyperuricemia (Elevated uric acid levels in the blood)
6. Elevated Inflammatory Markers
7. Endothelial Dysfunction
8. Prothrombotic State (Blood clotting)
9. Arterial Damage
10. Diabetes
iherb.com/blog/insulin-resi...
Many people who are insulin resistant are not even aware that they are and if your doctor doesn't test you and tell you that you are insulin resistant, how will you even have a clue? There are signs that can help you determine if you should ask your doctor to test you for IR. Here is a list of common ones :
High blood pressure (hypertension)
Overweight
Obesity
Skin tags (especially the neck or groin)
High cholesterol
High triglycerides
Fatty liver
Prediabetes
Diabetes
Enlarged prostate
Heart disease
Polycystic ovarian syndrome (abnormal periods)
I would look at IR as one step, higher up in a cascade of negative health steps where almost all roads lead to a worsening of health such as diabetes, CVD or organ damage! This cascade also involves ever increasing oxidative stress levels and elevated inflammatory markers in the body. This is a path that none of us want to go down or stay on and PwP certainly don't need IR.
So, what can we do to reduce insulin resistance and improve insulin sensitivity? A healthful diet is a very good starting point if you are able to stick to it, but for various reasons, people are often not able to maintain such a diet.
Regular exercise is another effective means to reduce insulin resistance while increasing insulin sensitivity. For some PwP, exercise is a difficult proposition if not almost impossible.
BERBERINE
There are also supplements that can help to reduce IR. One that I have written about before is Berberine which can reduce insulin resistance while increasing insulin sensitivity as discussed here:
ncbi.nlm.nih.gov/pmc/articl....
Here is a relevant quote :
' Berberine improves physiological stimulation of glucose via cascade reaction of insulin-like growth factor-1 (IGF-1), thus inducing secretion of insulin in the body, reducing insulin resistance, and improving sensitivity of liver, muscle tissues and fat to insulin (16). '
Berberine has also been discussed at length on this forum as being beneficial for PD via multiple pathways and mechanisms. Similarly, berberine is also useful for AD.
GRAPE SEED PROANTHOCYANIDIN EXTRACT
Another supplement that has shown the ability to reduce insulin resistance in people is Grape Seed Proanthocyanidin Extract (GSPE) as discussed in the following human study :
pubmed.ncbi.nlm.nih.gov/333...
Here is a relevant quote from the randomized controlled trial (RCT) :
' Forty-two participants completed the trial. After the intervention, the age, sex, baseline values, energy intake and physical activity as a covariate adjusted using ANCOVA for determine differences between groups. The MD (mean difference ±SEM) of HOMA-IR between the GSE group (-1.46 ± 0.45) and the placebo group (-0.48 ± 0.47), (p = 0.020), and the MD of insulin between the GSE group (-7.05 ± 2.11) and the placebo group (-1.71 ± 2.12), (p = 0.024), were significant. Although changes were observed in other variables, they were not statistically significant. '
Interesting about this GSPE study above, is the dose they used. Just 100mg per day to reduce IR. I take a minimum of 1200 mg/day.
MAGNESIUM
Another supplement that has shown the ability to reduce insulin resistance is Magnesium. Magnesium is significantly negatively correlated with IR. Magnesium is highly underrated for diabetes. The following study (2021) is interesting :
pubmed.ncbi.nlm.nih.gov/345...
Here is an interesting quote from the study :
' HOMA-IR increases as the Mg level decreases in advanced ages without obesity, especially in men with low eGFR.'
eGFR is a marker for how well the kidneys are filtering.
In this next study magnesium is shown to significantly lower insulin resistance in rheumatoid arthritis(RA) patients thus potentially reducing their chances of getting diabetes. RA patients are at increased risk of getting diabetes.
ncbi.nlm.nih.gov/pmc/articl...
Here is a relevant quote from the study :
' Statistically significant differences were found between FBS, insulin and HOMA-IR before and after consumption of oral magnesium (p<0.05). Our data suggested that magnesium supplementation reduces FBS, insulin and HOMA-IR in patients with rheumatoid arthritis. Thus, magnesium supplements may be an alternative method for prevention of type 2 diabetes in RA patients. '
CEYLON CINNAMON
The next supplement I want to mention for IR is Cinnamon, and of course the preferred form is Ceylon Cinnamon. Cinnamon also significantly lowers IR as discussed in the following study :
ncbi.nlm.nih.gov/pmc/articl...
Here is a relevant study quote :
' Weight and BMI decreased significantly in all intervention groups. The consumption of metformin and cinnamon significantly decreased insulin resistance (HOMA-IR) in comparison to the placebo and ginger groups (P < 0.05). '
VITAMIN D
The last supplement I would like to discuss and possibly the most important based on its multitude of positive health effects is vitamin D.
The following study discusses how in recent years it is becoming clearer through studies and research that vitamin D is a very significant factor when it comes to IR and vitamin D was shown to improve insulin sensitivity in this study at 5000 iu/day:
eje.bioscientifica.com/view...
Here is an important quote from the 6 month study in humans :
' At 6 months, mean 25(OH)D reached 127.6 ± 26.3 nmol/L and 51.8 ± 16.5 nmol/L in the treatment and placebo groups, respectively (P < 0.001). A beneficial effect of vitamin D3 compared with placebo was observed on M-value (mean change (95% CI): 0.92 (0.24–1.59) vs −0.03 (−0.73 to 0.67); P = 0.009) and disposition index (mean change (95% CI): 267.0 (−343.4 to 877.4) vs −55.5 (−696.3 to 585.3); P = 0.039) after 6 months. '
The M-value mentioned above is the value used for insulin sensitivity and the study shows a statistically significant positive change.
Here is another relevant quote from the study :
' In conclusion, this study showed that high-dose vitamin D supplementation for 6 months significantly improved peripheral insulin sensitivity, as assessed by the hyperinsulinemic-euglycemic clamp, and β-cell function in individuals at high risk of diabetes or with newly diagnosed type 2 diabetes.
So these five supplements have all shown the ability in people to decrease insulin resistance and or increase insulin sensitivity which is a healthful venture for people in general, whether you have diabetes or not and especially if you have PD or other disease.
There are many supplements that can reduce insulin resistance, but these five have very good safety profiles, studies to support their use for this purpose, are relatively inexpensive and have the ability to offer other health benefits with less chance for negative side effects.
Art