The ketogenic diet , or keto diet, has become one of the most popular diets in recent years for its ability to enhance fat loss, increase energy, improve athletic performance, and control appetite. But despite these benefits, research and decades of clinical experience have found the diet to increase the risk for multiple nutrient deficiencies. Read on to see what nutrients you should be watching to maximize your health on a ketogenic diet. What to Monitor on a Keto Diet?
The ketogenic diet is more popular than ever. The diet is extremely low in carbohydrates (usually less than 50 g/day), moderate in protein, and very high in fat. “Ketogenic” refers to the ability of the diet to generate high levels of compounds called ketones that are used as the main energy source instead of glucose [ 1 , 2 ].
The term was first coined by Dr. Russ Wilder of the Mayo Clinic in 1921, who used the diet to successfully treat epileptic children. However, with the introduction of effective anticonvulsant drugs, the ketogenic, or keto, diet fell out of favor with doctors. However, it was and still is used to successfully treat epileptic patients who don’t respond to drugs or surgery [ 1 , 2 ].
The diet has seen a resurgence in popularity in recent decades. Reported benefits range from weight loss and improved blood sugar control to increased energy and mental clarity. Research has backed some of these claims: the keto diet is more effective for weight loss, reducing blood sugar levels, and improving cholesterol and triglycerides than high-protein, calorie-restricted, and even low-fat diets (one RCT of 25 participants, one randomized crossover trial of 17 participants, three RTs of 159 participants) [ 3 , 4 , 5 , 6 , 7 ].
Beyond weight loss, the diet’s therapeutic potential has also been studied in type 2 diabetes , heart disease, brain trauma, Alzheimer’s disease, and cancer, with promising results [ 8 ].
While the diet may have multiple benefits, there are concerns that it can cause multiple nutrient imbalances due to its restriction of carbohydrates and its effects on how the body processes certain nutrients. Important Nutrients
Calcium is important for bones and teeth, blood vessel function, and muscle and nerve communication [ 9 ].
People on long-term keto diets often lose too much calcium in the urine in addition to having acidic urine.
High-fat diets can increase the amount of acid generated by the body, which the kidneys must filter out to maintain a stable blood pH. This leads to lower urine pH . Calcium from bones is also used to buffer the increased acid production, leading to higher calcium loss in the urine and lower bone density [ 10 , 11 , 12 , 13 ].
In addition, dietary calcium intake may be lower due to the limitation of calcium-rich foods such as fruits, vegetables, dairy, and enriched grains on the diet. Research in rats found that high-fat, low-carbohydrate diets reduced calcium absorption because fats would form indigestible soaps with calcium [ 14 , 15 ].
Too much calcium in the urine and acidic urine are major risk factors for kidney stones, which is why studies suggest that 3 – 6% of people on a long-term keto diet may develop stones within two years [ 16 ].
If a keto diet is something you are doing long-term or often, work with your doctor to monitor your kidney health by doing a regular urinalysis. Urinalysis includes tests such as urine pH, calcium crystals, and uric acid crystals, which can tell you when you’re at risk of kidney stones.
If you’re on a long-term keto diet, your doctor will often prescribe potassium citrate, which reduces the risk of stones by increasing pH and reducing the loss of calcium in the urine [ 16 , 17 ].
Keto-friendly foods high in calcium include sardines, salmon, spinach, and turnip greens [ 18 ].
Because blood calcium is tightly maintained within a narrow range you may need to occasionally check your bone mineral density (z-score, t-score) to determine if you are losing calcium from your bones [ 9 ]. 2) Magnesium
Magnesium is another mineral that has been observed to decrease substantially on a long-term keto diet. This mineral is extremely important for our bodies to produce energy and is required for our nerve cells and brain to function properly. It’s not surprising that deficiency has been associated with a wide range of conditions including heart disease, and migraines [ 19 , 20 , 21 , 22 ].
Symptoms of magnesium deficiency include muscle cramps, headaches , anxiety and nervousness, and constipation [ 22 ].
Decreased levels seen in people on a keto (low-carb) diet are likely due to eating fewer foods rich in magnesium such as fruits and grains [ 23 , 24 , 25 , 19 ].
Magnesium levels can be easily tested and easily corrected. Work with your doctor to find out if your magnesium levels are adequate.
Avocados, almonds, spinach, and salmon are all high in magnesium and low in carbohydrates. Magnesium supplements can also help [ 26 ]. 3) Iron
Even though keto diets usually involve eating ample quantities of meat, they also tend to reduce iron levels [ 27 , 13 , 28 ].
Iron is needed for energy production and making red blood cells and a deficiency can cause fatigue and trouble breathing during exercise [ 29 ].
Evidence suggests that iron deficiency may develop on the diet due to reduced absorption of iron caused by high amounts of fat [ 23 , 30 ].
Ask your doctor to check your ferritin levels to see how well your body is storing iron. You can increase your absorption of iron by eating more vitamin C -rich foods such as bell peppers and broccoli with iron rich-foods (or by supplementing with vitamin C). Also, avoid drinking tea and coffee with meals as these will decrease how much iron your body absorbs [ 31 , 32 , 33 , 34 ]. 4) Sodium
Sodium is an […]