Turnip is an edible root vegetable with an impressive nutritional profile. But could it be a good addition to a diabetic diet? There is a common belief in Pakistan that root vegetables should not be consumed by people with diabetes. Is this true? Let’s explore the scientific worth of turnip for diabetics.
ABOUT TURNIP
Turnip belongs to the Brassicaceae family (mustard family), which also includes other cruciferous vegetables such as broccoli, cabbage, cauliflower, kale, and Brussels sprouts. It is known as “Shaljam” in Pakistan.
In one of my previous articles, Cabbage: https://pharmahealths.com/cabbage-benefits-type-2-diabetes/ A Powerful Nutraceutical Ally in the Prevention and Management of Type 2 Diabetes, I discussed the remarkable health profile of cabbage for diabetic individuals. Similarly, turnip, which is typically creamy white with a purple top, also deserves attention. Some varieties may have a green-tinted or yellowish top.
Although turnip is not very popular, both its bulb and leaves possess promising health-promoting properties
NUTRITIONAL VALUE OF TURNIP
• Turnip is rich in potassium, nitrates, calcium, fiber, folate, magnesium, manganese, phosphorus, vitamin C, and tannins.
• It also contains low fat carbohydrates, protein, sinapic acid, ferulic acid, flavonoids (such as kaempferol glycoside, quercetin glycoside, and isorhamnetin glucoside), and bioactive compounds like sulforaphane and indole alkaloids.
ABOUT DIABETES
Diabetes mellitus is a chronic metabolic disorder characterized by high blood sugar (hyperglycemia) due to impaired insulin secretion or action. Over time, it can lead to several complications such as neuropathy, retinopathy, kidney disease, cardiovascular disorders, and depression.
With a sedentary lifestyle and poor dietary habits, especially low fiber intake, consumption of processed foods, sugary drinks, and junk food the global prevalence of diabetes continues to rise, creating a substantial burden on healthcare systems.
Currently, the focus of diabetes management is shifting toward plant based bioactive compounds. Among these, turnip has gained attention in animal studies for its hepatoprotective and antidiabetic effects. Let’s delve into how the aqueous extract of turnip exhibits antidiabetic properties.
TURNIP: A LOW GLYCEMIC INDEX AND HIGH FIBER VEGETABLE
Being low in calories and carbohydrates but rich in fiber, turnip can help regulate blood sugar levels. Its low glycemic index (GI) means it prevents sudden spikes in blood glucose and allows a slow, steady release of sugar into the bloodstream. Interestingly, this property remains stable whether the turnip is boiled or steamed.
TURNIP PROMOTES WEIGHT LOSS
Obesity is one of the key risk factors for diabetes. High fiber foods such as turnip promote satiety, reduce hunger, and aid in weight management, thereby indirectly helping to control blood sugar levels.
ANTI INFLAMMATORY EFFECTS OF TURNIP
According to Healthline, the breakdown products of glucosinolates, notably indoles and isothiocyanates, exhibit potent anti-inflammatory properties.
A compound called arvelexin, found in turnip, blocks pro-inflammatory mediators and reduces inflammation in human colon cells. Thus, incorporating turnip may help in mitigating chronic inflammation often associated with metabolic disorders like diabetes.
REDUCTION OF OXIDATIVE STRESS
Turnip’s rich nutritional composition makes it effective against oxidative stress, a major contributor to diabetes and its complications.
Vitamin C, along with other antioxidants present in turnip, helps neutralize free radicals and strengthens the immune system, thereby supporting overall metabolic health.
IMPORTANCE OF POLYPHENOLS AND FLAVONOIDS IN TURNIP FOR SUGAR CONTROL
Traditionally, turnip has been used in folk medicine for treating various ailments, including diabetes, due to its medicinal and therapeutic properties.
Its antidiabetic or antihyperglycemic effects are primarily attributed to its high content of polyphenols, flavonoids, and tannins, which act through several mechanisms:
1. Improvement of Peripheral Glucose Uptake: Turnip enhances glucose uptake in skeletal muscle and adipose tissue by promoting GLUT4 (glucose transporter type 4) translocation to the cell membrane. This process allows glucose to enter cells efficiently, improving insulin sensitivity.
2. Inhibition of Hepatic Gluconeogenesis: Normally, insulin suppresses glucose production (gluconeogenesis) in the liver by inhibiting key enzymes like phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (G6Pase).
However, in insulin resistance, this suppression fails, resulting in fasting hyperglycemia.
Turnip extract helps downregulate these enzymes, thereby reducing hepatic glucose output.
3. Enzyme Inhibition for Glucose Control: According to the National Center for Biotechnology Information (NCBI), turnip’s aqueous extract inhibits α-glucosidase and α-amylase, enzymes that break down dietary carbohydrates into glucose.
This inhibition helps delay glucose absorption and control postprandial (after-meal) sugar spikes.
4. Protection of Pancreatic Beta Cells: Quercetin, a flavonoid found in turnip, decreases plasma glucose levels and protects pancreatic beta cells from oxidative stress, supporting insulin secretion.
5. Enhanced Cellular Glucose Uptake: Kaempferol exhibits hypoglycemic effects by stimulating glucose uptake into body cells.
6. Hepatoprotective and Regenerative Effects: Turnip extract shows liver-protective properties, reducing hepatic damage and supporting regeneration of pancreatic cells, which is crucial in diabetes management.
7. Inhibition of Aldose Reductase: The flavonoid isorhamnetin inhibits aldose reductase, an enzyme linked with diabetic complications. To understand this better, let’s look at the role of the polyol pathway in diabetes.
ROLE OF POLYOL PATHWAY IN DIABETIC COMPLICATIONS
The polyol pathway is a minor route of glucose metabolism under normal conditions.
However, in chronic hyperglycemia, excessive activation of this pathway leads to the accumulation of sorbitol and reactive oxygen species (ROS) inside cells, resulting in oxidative stress and cellular toxicity.
The key enzyme, aldose reductase (AR), is found in the liver, kidneys, eyes (retina, lens, cornea), peripheral nerves, and blood vessels.
Overactivation of AR contributes to diabetic complications such as neuropathy, nephropathy, retinopathy, and cataract formation.
By inhibiting this enzyme, compounds like isorhamnetin from turnip may help reduce or delay these long-term complications.
CONCLUSION
Based on current animal studies and experimental evidence, turnip exhibits antidiabetic, antihyperglycemic, and hepatoprotective potential, despite being a root vegetable. It can safely be included in a diabetic diet in moderate amounts.
However, individuals with kidney problems should be cautious due to its potassium content. Likewise, those allergic to cruciferous vegetables should avoid it.
As always, moderation remains the key to achieving benefits without adverse effects.
FAQs
1. Is turnip good for people with diabetes?
Yes. Turnip is low in calories and carbohydrates but high in fiber and antioxidants. It helps regulate blood sugar levels, improve insulin sensitivity, and reduce oxidative stress, making it a healthy addition to a diabetic diet in moderation.
2. Can turnip increase blood sugar levels?
No. Turnip has a low glycemic index (GI), meaning it causes a slow and steady rise in blood sugar instead of sudden spikes, especially when boiled or steamed.
3. Can diabetics eat turnip leaves (Shaljam ke patte)?
Absolutely. Turnip greens are rich in fiber, vitamin C, calcium, and plant compounds that enhance glucose metabolism and protect against oxidative damage.
4. How often can diabetics eat turnip?
Turnip can be eaten 2 TO 3 times per week in moderate portions as part of a balanced meal plan. Always consult a healthcare professional if you are following a medically restricted diet.
5. Are there any side effects of eating turnip?
Turnip is generally safe, but those with kidney problems should consume it cautiously due to its potassium content. People allergic to cruciferous vegetables should avoid it.
DISCLAIMER
This article is for educational purposes only and does not replace professional medical advice. Individuals with diabetes or other chronic conditions should consult their physician or registered dietitian before making significant dietary changes or using any plant-based remedies.
CALL TO ACTION
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REFERENCES
1. National Center for Biotechnology Information (NCBI). Antidiabetic and hepatoprotective potential of Brassica rapa extract.
2. Healthline. The Science Backed Benefits of Glucosinolates and Isothiocyanates in Cruciferous Vegetables.
3. Altemimi A et al. (2017). Health-promoting bioactive compounds in Brassica vegetables: Role in metabolic health. Journal of Food Science and Technology.
4. American Diabetes Association. Dietary management and low glycemic index foods for diabetes control. 5. Park S. et al. (2014). Protective effects of turnip extract on hepatic oxidative stress in diabetic animal models. Nutrition Research.