Myth busted: Low-carb diets are nutritionally inadequate

By The Low Carb Clinic, 26th November 2019 - 1179 words (6 minutes)

Low-carb diets are sometimes criticised for being nutritionally inadequate.

Specifically, they are cited as being low in thiamine, folate, vitamins A, E and B6, calcium, magnesium, iron, and potassium, as well as missing antioxidants and phytonutrients. 

If this were true, it would be very worrying - such nutrients are essential to our wellbeing.  

But luckily, it isn’t true. And here’s a variety of low-carb foods for you to enjoy on a low-carb diet, rich in these vitamins and minerals.   

Vitamin B1 (thiamine) is important for energy metabolism and the growth and development of cells. Thiamine deficiency might cause a loss of appetite, fatigue, confusion, as well as muscle weakness and tingling. It is a water-soluble vitamin, so the body does not store it. Thiamine is found naturally in lots of foods – and in Australia, thiamine has also been added to many kinds of cereal and wheat products in national food fortification programs. 

It is recommended that we get about 1.2 milligrams of thiamine per day[1] (the recommended daily intake is the ‘RDI’).  

Here are some low-carb, high-thiamine foods:  

Or just: 

Folate (vitamin B9) is essential in the production of new cells (like red blood cells) and DNA synthesis, and also in the prevention of neural tube defects in babies. Folate deficiency can cause fatigue, weakness, mouth sores and grey hair. It is a water-soluble vitamin, so the body does not store it. Folate is found naturally in lots of foods – and in Australia, folic acid (the synthetic form of folate) has also been added to many wheat flours in national food fortification programs.  

It is recommended that we get approximately 400 micrograms of folate per day[2] (although the recommendations are different if you are pregnant).  

Here are some low-carb, high-folate foods:  

Or just: 

Vitamin A helps to maintain good eyesight, skin, and bones. It is a fat-soluble vitamin, so we need fat to absorb it, and it can be stored in the body over time. Vitamin A deficiency contributes to night blindness, dry skin, and eyes, poor wound healing, and acne. It is recommended that we get approximately 700 micrograms of vitamin A per day (for women) and 900 micrograms per day (for men)[3].  

Here are some low-carb, high-vitamin A foods:  

Or just:   

Vitamin E helps promote healthy skin and hair, balances cholesterol and hormones, and works as an antioxidant in the body. Vitamin E deficiency can lead to nerve problems, poor vision, muscle weakness, and poor immunity. Vitamin E is a fat-soluble vitamin, so it can be stored in the body.  

It is recommended that we get approximately 7 milligrams/day (for women) and 10 milligrams/day (for men) of vitamin E per day[4].  

Here are some low-carb, high vitamin E foods: 

Or just: 

Vitamin B6 helps the body to metabolise food energy and is important in the function of the nervous system, as well as immunity. B6 deficiency can cause dry skin and rashes, poor immune function, and low energy. It is recommended that we get approximately 1.3 milligrams of B6 per day[5].  

Here are some low-carb, high-B6 foods:  

Or just: 

Calcium is important for building and maintaining bones and teeth, as well as cardiovascular health and muscle tissue. Calcium deficiency can lead to weak fingernails and bones, muscle cramps, tingling, and numbness. Calcium is found naturally in lots of foods, but it’s also added to some foods in Australia as part of national fortification programs – for example, it is added to some orange juice, soy and almond milks, bread and breakfast cereals. It is recommended that we get about 1,000 mg of calcium per day[6] 

Here are some low-carb, high-calcium foods: 

Or just: 

It is recommended that we get about 320 mg/day (for women) and 420 mg/day (for men) of magnesium per day[7] 

Here are some low-carb, high magnesium foods: 

Or just: 

Iron is a mineral that helps to transport oxygen in the blood. There are two types of iron – haem iron, found in animal foods, and non-haem iron, found in both animal and plant foods (like beans and cereals). Haem iron is more readily absorbed than non-haem iron. Iron deficiency causes fatigue, breathlessness, paleness, and weakness. It is recommended that we get about 8mg (for men) and 18 mg (for women) of iron per day[8].  

Here are some low-carb, high-iron foods: 

Or just: 

Potassium is a mineral that stimulates the nerves and muscles in the body – including the heart. Potassium deficiency can lead to constipation, weakness, muscle cramps and heart palpitations. It is recommended that we get about 3,800 mg (for men) and 2,800 mg (for women) of potassium per day[9].

Here are some low-carb, high potassium foods: 

Or just: 

Phytonutrients are found in plants. Some common phytonutrients include carotenoids, flavonoids, and glycosylates. They can act as antioxidants, and so can help protect the body from oxidative stress, inflammation and free radical damage to cells.  

Low-carb foods high in phytonutrients include: 

• Pumpkin 
• Spinach 
• Kale 
• Blackberries 
• Dark chocolate (choose 90% or greater!) 
• Herbs (parsley, rosemary, thyme, basil, coriander, mint, oregano…) 
• Spices (ginger, cinnamon, clove, nutmeg, mustard powder, pepper, cumin, turmeric, chilli…) 
• Garlic & onion  
• Coffee 
• Broccoli 
• Cauliflower 
• Bok choy 
• Brussel sprouts 
• Cabbage 

Tea is very high in phytonutrients. There is a huge variety of teas on offer – try them warm or chilled, with ice, lemon, lime, cinnamon, cloves, nutmeg or ginger.

• Green 
• Chai 
• Matcha 
• Earl grey  
• Milk thistle 
• Dandelion  
• Peppermint 
• Lavender  
• St John’s Wort 

Antioxidants is a general term used to describe nutrients that help to protect the body against free radical damage or oxidative stress. Antioxidants include vitamin A, C, E, K as well as copper, zinc, and selenium: lots of foods have antioxidants in them. Prioritising nutrient density will automatically ensure you consume antioxidants.  

Here are some nutrient-dense, low-carb foods, high in antioxidants: 

Low-carbohydrate eating is not nutritionally inadequate.  

Eating a variety of low-carbohydrate whole foods will ensure you meet your nutritional needs – much more so than processed carbohydrates, grains, and cereals.  

With all of this in mind, it is important to note that being in a state of ketosis creates significant change all over the body – including in the way the cells produce energy and utilise essential vitamins and minerals. Ketones are a cleaner and more efficient fuel source: burning ketones actually produces far less oxidative stress in the body than burning carbohydrates. Ketones themselves can act as antioxidants[10][11].  

Low-carbohydrate eating also promotes positive hormonal changes – like lowered insulin – and can change the way our body uses certain vitamins and minerals. For example, the B-vitamins are especially important in carbohydrate metabolism, and the metabolism of vitamin C and glucose are intimately linked in the body. Studies assessing the recommended daily intakes of vitamins and minerals in humans are not necessarily applicable to a low-carbohydrate or ketogenic lifestyle. There is no doubt, however, that whole-food-based, low-carbohydrate eating is nutritionally complete – after all, it’s how we ate for most of human history.  

 

References

1. National Health and Medical Research Council. (2014, April). Thiamin. Retrieved from Nutrient Reference Values for Australia and New Zealand: https://www.nrv.gov.au/nutrients/thiamin 
2. National Health and Medical Research Council. (2014, April). Folate. Retrieved from Nutrient Reference Values for Australia and New Zealand: https://www.nrv.gov.au/nutrients/folate 
3. National Health and Medical Research Council. (2014, April). Vitamin A. Retrieved from Nutrient Reference Values for Australia and New Zealand: https://www.nrv.gov.au/nutrients/vitamin-a 
4. National Health and Medical Research Council. (2014, April). Vitamin E. Retrieved from Nutrient Reference Values for Australia and New Zealand: https://www.nrv.gov.au/nutrients/vitamin-e 
5. National Health and Medical Research Council. (2018, January). B6. Retrieved from Nutrient Reference Values for Australia and New Zealand: https://www.nrv.gov.au/nutrients/vitamin-b6 
6. Department of Human Services. (2013, April). Calcium. Retrieved from BetterHealth Channel: https://www.betterhealth.vic.gov.au/health/healthyliving/calcium 
7. National Health and Medical Research Council. (2014, April). Magnesium. Retrieved from Nutrient Reference Values for Australia and New Zealand: https://www.nrv.gov.au/nutrients/magnesium 
8. Department of Human Services. (2014, September). Iron Deficiency in Adults. Retrieved from BetterHealth Channel: https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/iron-deficiency-adults 
9. National Health and Medical Research Council. (2014, April). Potassium. Retrieved from Nutrient Reference Values for Australia and New Zealand: https://www.nrv.gov.au/nutrients/potassium 
10. Maalouf, M., Sullivan, P., Davis, L., & Kim, D. (2007). Ketones inhibit mitochondrial production of reactive oxygen species production following glutamate excitotoxicity by increasing NADH oxidation. Neuroscience, 145(1), 256-264. 
11. Gasior, M., Rogawski, M., & Hartman, A. (2006). Neuroprotective and disease-modifying effects of a ketogenic diet. Behavioral Pharmacology, 17(5), 431-439.