Medical Bulletin 04/ March/ 2024

Can a low-fat vegan diet reduce insulin requirement in type 1 diabetes?

According to a study published in the journal Clinical Diabetes, a low-fat vegan diet rich in fruits, vegetables, grains, and beans can help reduce insulin needs and improve insulin sensitivity and glycemic control in people with type 1 diabetes.

Type 1 diabetes is thought to be caused by an autoimmune reaction that destroys the beta cells in the pancreas that make insulin. Insulin is a hormone that helps move glucose (sugar) from the blood into muscle and liver cells to be used as energy. People with type 1 diabetes must take insulin because their body doesn’t produce enough. Some people with type 1 diabetes may also have insulin resistance, which is a condition in which cells don’t respond well to insulin and glucose remains in the blood. Insulin resistance is strongly influenced by dietary fat, which can inhibit glucose from entering the cells. Over time, high blood glucose levels can lead to health complications.

In the 12-week study, 58 adults with type 1 diabetes were randomly assigned to either a low-fat vegan group with no limits on calories or carbohydrates, or a portion-controlled group that reduced daily calorie intake for overweight participants and kept carbohydrate intake stable over time.

The results showed that in the low-fat vegan diet group, insulin requirements decreased by 28% and insulin sensitivity improved by 127% compared to the portion-controlled diet group. This was accompanied by an average weight loss of 11 pounds in the vegan group, while the portion-controlled group saw no significant change. Increased carbohydrate and fibre intake were associated with improved insulin sensitivity. Additionally, the vegan group experienced greater reductions in total cholesterol (32.3 mg/dL) and LDL cholesterol (18.6 mg/dL) compared to the portion-controlled group.

“With the cost of insulin remaining a concern for many, our groundbreaking research shows that a low-fat vegan diet that doesn’t restrict carbs may be the prescription for reducing insulin needs, managing blood sugar levels, and improving heart health in people with type 1 diabetes,” said Hana Kahleova, MD, PhD, the lead author of the study and director of clinical research at the Physicians Committee for Responsible Medicine.

Reference: Hana Kahleova; Tatiana Znayenko-Miller; Karen Smith; Cyrus Khambatta; Robby Barbaro; Macy Sutton; Danielle N. Holtz; Mark Sklar; Desiree Pineda; Richard Holubkov; Neal D. Barnard; Effect of a Dietary Intervention on Insulin Requirements and Glycemic Control in Type 1 Diabetes: A 12-Week Randomized Clinical Trial; Journal: Clinical Diabetes; https://doi.org/10.2337/cd23-0086

A study published in the journal PLOS Medicine revealed that women with premenstrual syndrome (PMS) or premenstrual dysphoric disorder (PMDD) have a higher risk of perinatal depression. Conversely, women with perinatal depression have a higher risk of developing premenstrual disorders.

Premenstrual disorders like PMS or PMDD and perinatal depression are similar in the way that symptoms appear in connection with hormonal changes.

The study, conducted by researchers at Karolinska Institute, analysed approximately 1,800,000 pregnancies that were registered in the Swedish Medical Birth Register between 2001 and 2018. Among these, they were able to identify nearly 85,000 women who suffered from perinatal depression. Additional national registers, such as the patient register and the drug register, were also used to identify women diagnosed with PMS or PMDD. These were then compared to a control group of nearly 850,000 birthing women who did not develop perinatal depression during the same period.

The results showed that women with premenstrual disorders were five times more likely to experience perinatal depression. Conversely, women who experienced perinatal depression were twice as likely to develop premenstrual disorders. The bidirectional association was noted for both prenatal and postnatal depression, regardless of history of psychiatric disorders.

"It is important that healthcare professionals who meet with women during pregnancy are aware of the link between premenstrual disorders and perinatal depression in order to provide well-informed advice," said Donghao Lu, Associate Professor at the Institute of Environmental Medicine, Karolinska Institute and last author of the paper.

Reference: Yang, Q., et al. (2024) The bidirectional association between premenstrual disorders and perinatal depression: A nationwide register-based study from Sweden. PLOS Medicine. doi.org/10.1371/journal.pmed.1004363.

Does ketogenic diet improve mental illness?

For people living with serious mental illness like schizophrenia or bipolar disorder, standard treatment with antipsychotic medications can be a double-edged sword. While these drugs help regulate brain chemistry, they often cause metabolic side effects such as insulin resistance and obesity, which are distressing enough that many patients stop taking the medications.

Now, a study led by Stanford Medicine researchers has found that a ketogenic diet not only restores metabolic health in patients with severe mental illness as they continue their medications, but it further improves their psychiatric conditions.

The results, published in the journal Psychiatry Research, suggested that a dietary intervention can be a powerful aid in treating mental illness.

In a four-month trial, Sethi and her team monitored 21 adult participants with schizophrenia or bipolar disorder, taking antipsychotic medications, and experiencing metabolic abnormalities. They followed a ketogenic diet, comprising 10% carbohydrates, 30% protein, and 60% fat, without calorie counting The research team tracked how well the participants followed the diet through weekly measures of blood ketone levels, with 14 fully adherent, six semi-adherent, and one non-adherent participant by trial's end.

The results revealed after four months of a ketogenic diet, none of the participants had metabolic syndrome, defined as having at least three of five conditions: abdominal obesity, elevated triglycerides, low HDL cholesterol, elevated blood pressure and elevated fasting glucose levels. Furthermore, the participants lost 10% of their body weight; reduced their waist circumference by 11% percent; and had lower blood pressure, body mass index, triglycerides, blood sugar levels and insulin resistance.

"Anything that improves metabolic health in general is probably going to improve brain health anyway. But the ketogenic diet can provide ketones as an alternative fuel to glucose for a brain with energy dysfunction," said Sethi.

Reference: Shebani Sethi, Diane Wakeham, Terrance Ketter, Farnaz Hooshmand, Julia Bjornstad, Blair Richards, Eric Westman, Ronald M Krauss, Laura Saslow. Ketogenic Diet Intervention on Metabolic and Psychiatric Health in Bipolar and Schizophrenia: A Pilot Trial. Psychiatry Research, 2024; 335: 115866 DOI: 10.1016/j.psychres.2024.115866