Keto Diet (KD) or a Low-Carb Diet was researched for several years. The diet’s strict guidelines advise consuming more fat and protein while cutting most carbohydrates and sugars out of your diet. This decrease in carbohydrates puts your body into a metabolic phase called ketosis[3]. It is a metabolic state in which your body utilizes fat for fuel rather than carbs[3]. And this process usually starts three to four days after excluding carbs from your diet[2].
Ketogenic diets can cause significant declines in blood sugar and insulin levels and the rise in ketones[3]. A Keto Diet forces your body to utilize fat; instead of glucose; for its energy demands[1]. Consequently; ketones are produced in larger quantities in the liver[1]. Also; ketones preferred by the brain can change the body’s metabolism – from glucose-burning to fat-burning[1].
It has recently been suggested as adjuvant therapy in treating cancer[4]. Good evidence from 2 – 3 studies are present for prostate cancer; colon cancer; pancreatic Cancer and lung cancer[4]; neuroblastoma also comes into this category[4].KDs target the Warburg effect; a biochemical phenomenon in which cancer cells predominantly use glycolysis instead of oxidative phosphorylation to generate ATP[4]. This alteration in the metabolism of cancer cells and associated stromal cells decreases glucose availability and increases the ketones as the only available energy source; which causes cancerous cells to be devoid of energy and hence unable to grow and spread[1].
KD can be achieved either with calorie restriction or an isocaloric diet; with no variation in total calories from the patient’s prior diet[1].
While isocaloric KD may be somewhat advantageous; caloric restriction is considered an essential part of an anticancer KD[1]. Caloric restriction helps the body retain ketones and reduces caloric drivers of cancer growth pathways[1].
The most substantial proof of more than three studies for a tumour-suppressing effect of the keto diet has been reported for glioblastoma[1][4]. Few clinical trials using an isocaloric ketogenic diet as cancer therapy for patients have been conducted. No clinical trials have been published until the date on calorie-restricted KD[1].
FOODS TO EAT
- In meat: red meat; steak; ham; sausage; bacon; chicken etc.[3].
- In fatty fishes: salmon; trout; tuna etc.[3].
- In eggs: pastured eggs or omega-3 whole eggs[3].
- In butter and cream: heavy cream and grass-fed butter[3].
- In cheese: unprocessed cheeses like cheddar; goat; mozzarella or blue cheese; cream cheese[3].
- In nuts and seeds: almonds; walnuts; flaxseeds; chia seeds etc.[3].
- In healthy oils: coconut oil; avocado oil and extra virgin olive oil.[3].
- Avocados: Freshly made guacamole or whole avocados[3].
- In low carb veggies: green vegetables; onion; peppers etc.[3].
- In condiments: salt; herbs; peppers and spices[3].
FOODS TO AVOID
Usually; high carb food should be restricted.
List of such foods includes:-
- sugary foods: fruit juice; smoothies; cake; ice cream; candy; etc. [3].
- Grains or starches: wheat-based products; rice; pasta; cereal; etc. [3].
- Fruits: all fruit; except tiny portions of berries like strawberries etc.[3].
- Beans or legumes: peas; kidney beans; lentils etc. [3].
- root vegetables and tubers: potatoes; sweet potatoes; carrots; etc.[3].
- low fat or diet products: low-fat mayonnaise; condiments and salad dressings[3].
- Some condiments or sauces: barbecue sauce; honey mustard; ketchup; etc.[3].
- Unhealthy fats: processed vegetable oils; etc. [3].
- alcohol: beer; wine; liquor; etc.[3].
- Sugar-free diet foods: sugar-free candies; sweeteners; desserts; etc.[3].
Keto diets for cancer treatment are often lower; ranging from 5% to as low as 0.1% carbohydrate; with protein content around 5-15%; and fat making up the rest; typically 80 to 90% or greater[5].
THE SCIENCE BEHIND KETO DIET AND CANCER
The Director of the Sandra and Edward Meyer Cancer Center at Weill Cornell Medical College; Dr Lewis Cantley; is a leading cancer researcher. Dr Cantley found a crucial enzyme known as Pi3K that helped understand the link between Cancer and insulin and how cancer genes cause Cancer in our bodies[5]. He proceeds to study extensively how the keto diet affects cancer cells[5].
All cells require glucose as a source of energy; and healthy cells use mitochondria to convert glucose into energy[5]. Cancer cells; however; use a different method to metabolize sugar[5]. Glucose tests are usually applied to determine where tumours are present in the body[5]. Glucose is labelled so that it can be identified on scans; then jabbed into the body; where it goes right to the tumour site because the cells are quite literally eating up the sugar[5].
So it makes sense that restraining cancer cells’ access to sugar may aid cancer treatments to be even more efficient[5].
But as Dr Cantley explains; a decline in blood sugar is just one of at least five distinctive ways that the keto diet may be efficient in fighting Cancer; in combination with evidence-based treatment plans that often involve some combination of chemotherapy; radiation therapy; and cancer surgery[5]:-
- Reduction of blood glucose levels- Lessening the availability of circulating blood sugar means decreasing the fuel source for cancer cells[5].
- Reduction in insulin levels- Insulin is an anabolic hormone that makes cells grow; including cancer cells[5]. Reducing insulin levels can mean delaying tumour growth[5].
- Lower levels of IGF-1- Insulin-like growth factor 1 is a hormone that acts as a protein growth signal for Cancer [5]. A Keto diet means lower insulin levels; which means less IGF-1 and the potential for reduced cancer risk and reduced tumour growth[5].
- Reduce the tumour’s ability to produce VEG-F- VEG-F (vascular endothelial growth factor) is a protein required to grow blood vessels to supply food and oxygen to tumours[5]. Interfering with VEG-F means obstruction in the tumour blood supply[5].
- Less visceral fat- Visceral fat is the abdominal fat deep under the skin; deposited around organs like the liver; intestines and pancreas[5]. High quantities of visceral fat are linked with various health issues; including colorectal Cancer; postmenopausal breast cancer; pancreatic; uterine Cancer and oesophagal cancer[5]. Little visceral fat inherently reduces our risk for these kinds of cancers[5].
EVIDENCE FROM HUMAN AND CLINICAL STUDIES FOR CANCER
- Two female patients with advanced-stage malignant Astrocytoma tumours were given a Ketogenic diet[1]. The results displayed promising potential[1].
- A Ketogenic dietary trial was conducted over ten patients with advanced Cancer for 26-28 days[1]. The extent of ketosis associated with stable disease or partial remission[1].
- Sixteen patients with advanced metastatic cancers and no standard therapy options were told to follow a Ketogenic diet[1]. Many positive effects were seen in those who finished the diet[1].
- In 2017; a systematic review was conducted assessing the clinical evidence of the Ketogenic diet on Cancer [1]. The study highlighted some crucial limitations of all clinical trials to date:-
- Most couldn’t assess the anti-tumour effects[1].
- Small sizes of sample and non-rigorous study designs make comparisons and conclusions very difficult[1].
- No two studies obeyed the same dietary protocol[1].
- In many studies; the ketogenic diet of patient’s is not supervised[1].
- Intravenous infusions of the Ketogenic diet exhibited no significant difference in tumour growth amongst the three groups[1].
PROS AND CONS OF KETO DIET
Although the ketogenic diet is ordinarily safe for most healthy people; there may be some primary side effects while your body adapts[3]
There’s some anecdotal proof of these effects; often regarded as the keto flu[3].
Some Keto flu symptoms include diarrhoea; constipation; and vomiting[3]. Other less frequent symptoms include:
- lacking energy and mental function[3]
- increased hunger[3]
- sleep problems[3]
- nausea[3]
Ketones are a kind of acid produced by your liver and then sent into your bloodstream[2]. Too many ketones can cause dehydration and change the chemical balance of your blood[2].
Cutting out whole food groups can also be challenging to remain long-term; and most people regain some weight or all of the weight lost when they leave the Keto diet and return to a less extreme diet[2].
Many keto diet-safe foods include red meat; which can heighten your cancer risk[2].
In addition; diets high in fat are linked with heart disease and obesity[2]. Keto diet helps to lose weight[3]; help with diabetes[3]; and treat Alzheimer’s disease[3]; epilepsy etc.[3].
A cancer patient should consult a doctor before considering any Keto diet because it can be beneficial for others and can be harmful to someone[2]. Depending on your type of cancer or cancer treatment; your body may not be able to break down the proteins and fats; leading to other digestive problems[2].
Therefore it is mandatory to talk to your doctor before going for a Keto diet[2].
